Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Br J Haematol ; 203(2): 319-326, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37583261

RESUMO

Sickle cell anaemia (SCA) is a monogenic disease with a highly variable clinical course. We aimed to investigate associations between microvascular function, haemolysis markers, blood viscosity and various types of SCA-related organ damage in a multicentric sub-Saharan African cohort of patients with SCA. In a cross-sectional study, we selected seven groups of adult patients with SS phenotype in Dakar and Bamako based on the following complications: leg ulcer, priapism, osteonecrosis, retinopathy, high tricuspid regurgitant jet velocity (TRV), macro-albuminuria or none. Clinical assessment, echocardiography, peripheral arterial tonometry, laboratory tests and blood viscosity measurement were performed. We explored statistical associations between the biological parameters and the six studied complications. Among 235 patients, 58 had high TRV, 46 osteonecrosis, 43 priapism, 33 leg ulcers, 31 retinopathy and 22 macroalbuminuria, whereas 36 had none of these complications. Multiple correspondence analysis revealed no cluster of complications. Lactate dehydrogenase levels were associated with high TRV, and blood viscosity was associated with retinopathy and the absence of macroalbuminuria. Despite extensive phenotyping of patients, no specific pattern of SCA-related complications was identified. New biomarkers are needed to predict SCA clinical expression to adapt patient management, especially in Africa, where healthcare resources are scarce.


Assuntos
Anemia Falciforme , Úlcera da Perna , Osteonecrose , Priapismo , Doenças Retinianas , Masculino , Adulto , Humanos , Hemólise , Viscosidade Sanguínea , Estudos Transversais , Microcirculação , Senegal , Úlcera da Perna/etiologia , Doenças Retinianas/etiologia
2.
Blood ; 136(2): 247-256, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32285120

RESUMO

Microparticles (MPs) are submicron extracellular vesicles exposing phosphatidylserine (PS), detected at high concentration in the circulation of sickle cell anemia (SS) patients. Several groups studied the biological effects of MPs generated ex vivo. Here, we analyzed for the first time the impact of circulating MPs on endothelial cells (ECs) from 60 sickle cell disease (SCD) patients. MPs were collected from SCD patients and compared with MPs isolated from healthy individuals (AA). Other plasma MPs were purified from SS patients before and 2 years after the onset of hydroxyurea (HU) treatment or during a vaso-occlusive crisis and at steady-state. Compared with AA MPs, SS MPs increased EC ICAM-1 messenger RNA and protein levels, as well as neutrophil adhesion. We showed that ICAM-1 overexpression was primarily caused by MPs derived from erythrocytes, rather than from platelets, and that it was abolished by MP PS capping using annexin V. MPs from SS patients treated with HU were less efficient to induce a proinflammatory phenotype in ECs compared with MPs collected before therapy. In contrast, MPs released during crisis increased ICAM-1 and neutrophil adhesion levels, in a PS-dependent manner, compared with MPs collected at steady-state. Furthermore, neutrophil adhesion was abolished by a blocking anti-ICAM-1 antibody. Our study provides evidence that MPs play a key role in SCD pathophysiology by triggering a proinflammatory phenotype of ECs. We also uncover a new mode of action for HU and identify potential therapeutics: annexin V and anti-ICAM-1 antibodies.


Assuntos
Anemia Falciforme , Micropartículas Derivadas de Células/metabolismo , Endotélio Vascular/metabolismo , Hidroxiureia/administração & dosagem , Molécula 1 de Adesão Intercelular/sangue , RNA Mensageiro/sangue , Adolescente , Anemia Falciforme/sangue , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/patologia , Anemia Falciforme/fisiopatologia , Endotélio Vascular/patologia , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Inflamação/sangue , Inflamação/tratamento farmacológico , Inflamação/patologia , Inflamação/fisiopatologia , Masculino
3.
Br J Haematol ; 192(3): 634-642, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33249569

RESUMO

Although most individuals with sickle cell disease (SCD) live in sub-Saharan Africa, the natural history of the disease on this continent remains largely unknown. Intravascular haemolysis results in activation of circulating blood cells and release of microparticles (MPs) that exert pro-inflammatory effects and contribute to vascular damage. We designed a case-control study nested in the CADRE cohort (Coeur-Artère-DRÉpanocytose, clinical trials.gov identifier NCTO3114137) and based on extreme phenotypes, to analyse blood cell-derived MPs in 232 adult SS patients at steady state in Bamako and Dakar. Thirty-six healthy adult controls matched by age and sex were recruited in Bamako. The MPs concentrations were higher in SS patients compared to AA controls with a predominance of erythrocyte- and reticulocyte-derived MPs. These erythroid-derived MPs were significantly lower in patients with retinopathy (P = 0·022). Reticulocyte-derived MPs were significantly negatively and positively associated with a history of priapism (P = 0·020) and leg ulcers (P = 0·041) respectively. We describe for the first time the comparative patterns of plasma MPs in healthy subjects and patients with SCD living in sub-Saharan Africa and exhibiting various complications. Because our present results show no clear pattern of correlation between erythroid MPs and the classical hyper-haemolytic complications, we hypothesise a weak relevance of the hyper-haemolysis versus hyper-viscous paradigm in Africa.


Assuntos
Anemia Falciforme/complicações , Micropartículas Derivadas de Células/patologia , Doenças Vasculares/etiologia , Adulto , África Subsaariana/epidemiologia , Anemia Falciforme/patologia , Estudos de Casos e Controles , Feminino , Hemólise , Humanos , Masculino , Doenças Vasculares/patologia , Adulto Jovem
4.
Br J Haematol ; 183(4): 648-660, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30334577

RESUMO

Sickle Cell Disease (SCD) is an increasing global health problem and presents significant challenges to European health care systems. Newborn screening (NBS) for SCD enables early initiation of preventive measures and has contributed to a reduction in childhood mortality from SCD. Policies and methodologies for NBS vary in different countries, and this might have consequences for the quality of care and clinical outcomes for SCD across Europe. A two-day Pan-European consensus conference was held in Berlin in April 2017 in order to appraise the current status of NBS for SCD and to develop consensus-based statements on indications and methodology for NBS for SCD in Europe. More than 50 SCD experts from 13 European countries participated in the conference. This paper aims to summarise the discussions and present consensus recommendations which can be used to support the development of NBS programmes in European countries where they do not yet exist, and to review existing programmes.


Assuntos
Anemia Falciforme/diagnóstico por imagem , Anemia Falciforme/genética , Anemia Falciforme/epidemiologia , Conferências de Consenso como Assunto , Europa (Continente)/epidemiologia , Feminino , Humanos , Recém-Nascido , Masculino , Triagem Neonatal , Guias de Prática Clínica como Assunto
5.
Am J Hematol ; 93(11): 1411-1419, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30132969

RESUMO

In order to identify very early prognostic factors that can provide insights into subsequent clinical complications, we performed a comprehensive longitudinal multi-center cohort study on 57 infants with sickle cell anemia (55 SS; 2 Sß°) during the first 2 years of life (ClinicalTrials.gov: NCT01207037). Time to first occurrence of a severe clinical event-acute splenic sequestration (ASS), vaso-occlusive (VOC) event requiring hospitalization, transfusion requirement, conditional/ abnormal cerebral velocities, or death-was used as a composite endpoint. Infants were recruited at a mean age of 4.4 ±1 months. Median follow-up was 19.4 months. During the study period, 38.6% of infants experienced ≥1 severe event: 14% ASS, 22.8% ≥ 1 VOC (median age: 13.4 and 12.8 months, respectively) and 33.3% required transfusion. Of note, 77% of the cohort was hospitalized, with febrile illness being the leading cause for admission. Univariate analysis of various biomarkers measured at enrollment showed that fetal hemoglobin (HbF) was the strongest prognostic factor of subsequent severe outcome. Other biomarkers measured at enrolment including absolute neutrophil or reticulocyte counts, expression of erythroid adhesion markers, % of dense red cells, cellular deformability or ϒ-globin genetic variants, failed to be associated with severe clinical outcome. Multivariate analysis demonstrated that higher Hb concentration and HbF level are two independent protective factors (adjusted HRs (95% CI) 0.27 (0.11-0.73) and 0.16 (0.06-0.43), respectively). These findings imply that early measurement of HbF and Hb levels can identify infants at high risk for subsequent severe complications, who might maximally benefit from early disease modifying treatments.


Assuntos
Anemia Falciforme/diagnóstico , Índice de Gravidade de Doença , Anemia Falciforme/complicações , Anemia Falciforme/terapia , Biomarcadores/análise , Transfusão de Sangue , Estudos de Coortes , Feminino , Hemoglobina Fetal/análise , Hemoglobinas/análise , Hospitalização , Humanos , Lactente , Estudos Longitudinais , Masculino , Prognóstico
6.
Br J Haematol ; 173(1): 145-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26846309

RESUMO

Vaso-occlusive crisis (VOC) is the main acute complication in sickle cell anaemia (SS) and several clinical trials are investigating different drugs to improve the clinical severity of SS patients. A phase III study is currently exploring the profit of Velopoloxamer in SS during VOCs. We analysed, in-vitro, the effect of poloxamer (P188) on red blood cell (RBC) properties by investigating haemorheology, mechanical and adhesion functions using ektacytometry, microfluidics and dynamic adhesion approaches, respectively. We show that poloxamer significantly reduces blood viscosity, RBC aggregation and adhesion to endothelial cells, supporting the beneficial use of this molecule in SS therapy.


Assuntos
Anemia Falciforme/sangue , Viscosidade Sanguínea/efeitos dos fármacos , Agregação Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Poloxâmero/farmacologia , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/patologia , Adesão Celular/efeitos dos fármacos , Membrana Eritrocítica/patologia , Feminino , Humanos , Masculino
7.
J Biol Chem ; 289(16): 11512-11521, 2014 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-24616094

RESUMO

Vaso-occlusive crises are the main acute complication in sickle cell disease. They are initiated by abnormal adhesion of circulating blood cells to vascular endothelium of the microcirculation. Several interactions involving an intricate network of adhesion molecules have been described between sickle red blood cells and the endothelial vascular wall. We have shown previously that young sickle reticulocytes adhere to resting endothelial cells through the interaction of α4ß1 integrin with endothelial Lutheran/basal cell adhesion molecule (Lu/BCAM). In the present work, we investigated the functional impact of endothelial exposure to hydroxycarbamide (HC) on this interaction using transformed human bone marrow endothelial cells and primary human pulmonary microvascular endothelial cells. Adhesion of sickle reticulocytes to HC-treated endothelial cells was decreased despite the HC-derived increase of Lu/BCAM expression. This was associated with decreased phosphorylation of Lu/BCAM and up-regulation of the cAMP-specific phosphodiesterase 4A expression. Our study reveals a novel mechanism for HC in endothelial cells where it could modulate the function of membrane proteins through the regulation of phosphodiesterase expression and cAMP-dependent signaling pathways.


Assuntos
Anemia Falciforme/metabolismo , Antidrepanocíticos/farmacologia , Moléculas de Adesão Celular/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/biossíntese , Células Endoteliais/metabolismo , Hidroxiureia/farmacologia , Sistema do Grupo Sanguíneo Lutheran/metabolismo , Reticulócitos/metabolismo , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/genética , Anemia Falciforme/patologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Moléculas de Adesão Celular/genética , AMP Cíclico/genética , AMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/genética , Células Endoteliais/patologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/genética , Humanos , Células K562 , Sistema do Grupo Sanguíneo Lutheran/genética , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Reticulócitos/patologia , Sistemas do Segundo Mensageiro/efeitos dos fármacos , Sistemas do Segundo Mensageiro/genética , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
9.
Eur J Haematol ; 91(2): 164-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23668236

RESUMO

INTRODUCTION: Coinheritance of α-thalassemia influences the clinical and hematological phenotypes of ß-hemoglobinopathies (ß-thalassemia and sickle cell disease) and when present together in significant frequency within a population, a spectrum of clinical forms is observed. Precise molecular characterization of α-thalassemia is important in understanding their disease-modifying role in ß-hemoglobinopathies and for diagnostic purposes. PATIENTS AND METHODS: Because currently used approaches are labor/cost-intensive, time-consuming, error-prone in certain genotype combinations and not applicable for large epidemiological screening, we developed a systematic stepwise strategy to overcome these difficulties. We successfully applied this to characterize the α-globin gene status in 150 Omani cord blood samples with Hb Barts and 32 patients with HbH disease. RESULTS: We observed a good correlation between α-globin genotypes and level of Hb Bart's with the Hb Bart's levels significantly higher in both deletional and non-deletional α-globin genotypes. The most common α-globin genotype in HbH cases was α(TSaudi) α/α(TSaudi) α (n = 16; 50%) followed by -α(3.7) /-(MED) (n = 10; 31%). This approach detects also the α-globin gene triplication as exemplified by the study of a family where the ß-globin gene defect failed to explain the ß-thalassemia intermedia phenotype. CONCLUSION: Molecular characterization of α-thalassemia is complex due to high sequence homology between the duplicated α-globin genes and to the existence of a variety of gene rearrangements (small and large deletions of various sizes) and punctual substitutions (non-deletional alleles). The novelty of our strategy resides, not in the individual technical steps per se but in the reasoned sequential order of their use taking into consideration the hematological phenotype as well.


Assuntos
Testes Genéticos , Talassemia alfa/diagnóstico , Índices de Eritrócitos , Ordem dos Genes , Testes Genéticos/métodos , Genótipo , Humanos , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Prevalência , alfa-Globinas/genética , Talassemia alfa/epidemiologia , Talassemia alfa/genética , Talassemia beta/diagnóstico , Talassemia beta/genética
10.
J Hum Genet ; 57(10): 665-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22854539

RESUMO

The objective of our present study was to develop a warfarin dosing algorithm for the Omani patients, as performances of warfarin dosing algorithms vary across populations with impact on the daily maintenance dose. We studied the functional polymorphisms of CYP2C9, CYP4F2 and VKORC1 genes to evaluate their impact on the warfarin maintenance dose in an admixed Omani patient cohort with Caucasian, African and Asian ancestries. We observed a 64-fold inter-patient variability for warfarin to achieve stable international normalized ratio in these patients. Univariate analysis revealed that age, gender, weight, atrial fibrillation, deep vein thrombosis/pulmonary embolism and variant genotypes of CYP2C9 and VKORC1 loci were significantly associated with warfarin dose in the studied patient population. However, multiple regression model showed that only the atrial fibrillation, and homozygous CYP2C9 variant genotypes (*2/*3 and *3/*3) and VKORC1 GA and AA genotypes remained significant. A multivariate model, which included demographic, clinical and pharmacogenetic variables together explained 63% of the overall inter-patient variability in warfarin dose requirement in this microgeographically defined, ethnically admixed Omani patient cohort on warfarin. This locally developed model performed much better than the International Warfarin Pharmacogenetics Consortium (IWPC) model as the latter could only explain 34% of the inter-patient variability in Omani patients. VKORC1 3673G>A polymorphism emerged as the single most important predictor of warfarin dose variability, even in this admixed population (partial R(2)=0.45).


Assuntos
Algoritmos , Farmacogenética/métodos , Varfarina/administração & dosagem , Adulto , Idoso , Hidrocarboneto de Aril Hidroxilases/genética , Fibrilação Atrial/tratamento farmacológico , Citocromo P-450 CYP2C9 , Sistema Enzimático do Citocromo P-450/genética , Família 4 do Citocromo P450 , Cálculos da Dosagem de Medicamento , Etnicidade/genética , Feminino , Estudos de Associação Genética , Loci Gênicos , Genética Populacional/métodos , Genótipo , Humanos , Modelos Lineares , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Oxigenases de Função Mista/genética , Omã/etnologia , Polimorfismo Genético , Estudos Prospectivos , Trombose Venosa/tratamento farmacológico , Vitamina K Epóxido Redutases
11.
Hum Biol ; 84(1): 67-77, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22452429

RESUMO

This is the first study to evaluate the spectrum and prevalence of dose-predictive genetic polymorphisms of the CYP2C9, CYP4F2 and VKORC1 loci together, in a geographically defined, ethnically admixed healthy adult Omani population sharing common lifestyle/environmental factors. Since the present-day Omani population is the result of an admixture of Caucasian, African and Asian ancestries, we compared the pharmacogenetic profile of these three loci in this population. Interestingly, the Omani pharmacogenetic profile, in terms of allele and genotype distribution, has values that are intermediate between Caucasians and African Americans, the African admixture further substantiated by the presence of the CYP2C9*8 allele. However, limitations and usefulness of such comparisons warrant caution, as the data from pharmacogenetic literature do not always represent bona fide population categories. Furthermore, definition of study population based on microgeographical scale would be more appropriate in pharmacogenetic research rather than the flawed racial, ethnic, or social categorizations since pharmacogenetic variation is clinal, and genetic influences will be further altered by lifestyle and environmental factors.


Assuntos
Anticoagulantes/farmacologia , Hidrocarboneto de Aril Hidroxilases/genética , Sistema Enzimático do Citocromo P-450/genética , Oxigenases de Função Mista/genética , Varfarina/farmacologia , Adulto , Hidrocarboneto de Aril Hidroxilases/metabolismo , Distribuição de Qui-Quadrado , Citocromo P-450 CYP2C9 , Sistema Enzimático do Citocromo P-450/metabolismo , Família 4 do Citocromo P450 , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Oxigenases de Função Mista/metabolismo , Omã , Polimorfismo Genético , Prevalência , Vitamina K Epóxido Redutases
12.
Biochim Biophys Acta Biomembr ; 1864(10): 183980, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35654147

RESUMO

Plasmodium falciparum, a dangerous parasitic agent causing malaria, invades human red blood cells (RBCs), causing hemolysis and microvascular obstruction. These and other pathological processes of malaria patients are due to metabolic and structural changes occurring in uninfected RBCs. In addition, infection activates the production of microparticles (MPs). ATP and byproducts are important extracellular ligands modulating purinergic signaling within the intravascular space. Here, we analyzed the contribution of uninfected RBCs and MPs to the regulation of extracellular ATP (eATP) of RBCs, which depends on the balance between ATP release by specific transporters and eATP hydrolysis by ectonucleotidases. RBCs were cultured with P. falciparum for 24-48 h prior to experiments, from which uninfected RBCs and MPs were purified. On-line luminometry was used to quantify the kinetics of ATP release. Luminometry, colorimetry and radioactive methods were used to assess the rate of eATP hydrolysis by ectonucleotidases. Rates of ATP release and eATP hydrolysis were also evaluated in MPs. Uninfected RBCs challenged by different stimuli displayed a strong and transient activation of ATP release, together with an elevated rate of eATP hydrolysis. MPs contained ATP in their lumen, which was released upon vesicle rupture, and were able to hydrolyze eATP. Results suggest that uninfected RBCs and MPs can act as important determinants of eATP regulation of RBCs during malaria. The comparison of eATP homeostasis in infected RBCs, ui-RBCs, and MPs allowed us to speculate on the impact of P. falciparum infection on intravascular purinergic signaling and the control of the vascular caliber by RBCs.


Assuntos
Malária , Plasmodium falciparum , Trifosfato de Adenosina/metabolismo , Eritrócitos/metabolismo , Homeostase , Humanos , Malária/metabolismo , Plasmodium falciparum/metabolismo
13.
Haematologica ; 96(4): 534-42, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21228039

RESUMO

BACKGROUND: All the cellular partners of the vascular system and especially endothelial cells are involved in the pathophysiology of the vasoocclusive crises associated with sickle cell disease. In sickle cell disease, circulating cells adhere abnormally to endothelial cells in a chronic pro-inflammatory context. Hydroxycarbamide is the only drug with demonstrated efficacy to reduce the frequency of vasoocclusive crises. Here, we investigated the effects of hydroxycarbamide and/or cytokines on the expression of genes related to adhesion events in endothelial cells from three different vascular sites. DESIGN AND METHODS: Endothelial cells representative of the macro- (HUVEC) or microcirculation (TrHBMEC and HPMEC) were grown in the presence or absence of hydroxycarbamide and/or cytokines (TNFα and IFNγ). Expression of genes encoding adhesion proteins was analyzed by RQ-PCR, ELISA, flow cytometry, in situ ELISA for extracellular matrix proteins, and Western blot. RESULTS: In cells from the microcirculation, expression of TSP-1, vWF, and PECAM-1 genes was decreased by hydroxycarbamide and/or cytokine treatment at the mRNA level. In the macro-circulation their expression was unaffected or increased. Hydroxycarbamide significantly decreased vWF incorporated in the TrHBMEC extracellular matrix. CD36 mRNA was strongly down-regulated by cytokines in HPMEC, the only cell type in which it is expressed. Hydroxycarbamide decreased soluble PECAM-1 in HUVEC supernatants. CONCLUSIONS: Our results highlight the heterogeneity of vascular endothelial cell responses to hydroxycarbamide and/or cytokines depending upon their origin. They also suggest that hydroxycarbamide has an anti-adhesogenic effect on endothelial cells, but by mechanisms which could vary according to their macro- or microcirculation and organ origin.


Assuntos
Anemia Falciforme/genética , Anemia Falciforme/metabolismo , Moléculas de Adesão Celular/genética , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hidroxiureia/farmacologia , Anemia Falciforme/fisiopatologia , Antidrepanocíticos/farmacologia , Moléculas de Adesão Celular/metabolismo , Células Cultivadas , Perfilação da Expressão Gênica , Humanos , Análise em Microsséries , Trombospondina 1/genética , Fator de von Willebrand/genética
14.
Pharmacogenet Genomics ; 20(4): 257-68, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20216336

RESUMO

BACKGROUND AND OBJECTIVE: The clinical hallmarks of sickle cell disease (SCD) are vaso-occlusive crises (VOC) triggered by red blood cells (RBC) stiffening and abnormal adhesion to vascular endothelial cells (VEC) in the context of chronic inflammation, cell activation, and vascular tone abnormalities. Hydroxycarbamide (HC) is the only drug with a proven efficacy in decreasing VOC frequency. HC decreases RBC stiffening, modulates adhesion protein expression by RBC and VEC, and reduces endothelin-1 production by VEC. Our objective was to test whether HC could also affect inflammation through its action on VEC. METHODS: We used microarrays to study the effect of HC on the transcriptome of transformed human bone marrow endothelial cell, a cell line derived from bone marrow microcirculation (the predilection site of VOC), in basal and proinflammatory conditions. Microarray results were confirmed by real-time quantitative PCR and protein analysis on transformed human bone marrow endothelial cell (TrHBMEC) and on two other VEC types in the primary culture: human pulmonary microcirculation endothelial cell (HPMEC) and human umbilical vein endothelial cell (HUVEC a classical model for the macrocirculation). RESULTS: HC had a significant effect on the expression of genes of the 'inflammation pathway'. Strikingly, it stimulates the expression of proinflammatory genes such as IL1A, IL1B, IL6, IL8, CCL2, CCL5, CCL20, and CCL8 in all the tested VEC types. CONCLUSION: Our study confirms that VECs are significant targets of HC in the context of SCD and identifies its earlier unsuspected action on another major component of SCD pathophysiology, that is, the 'inflammation pathway'.


Assuntos
Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/metabolismo , Antidrepanocíticos/farmacologia , Citocinas/biossíntese , Hidroxiureia/farmacologia , Mediadores da Inflamação/metabolismo , Anemia Falciforme/genética , Linhagem Celular , Quimiocinas CC/biossíntese , Quimiocinas CC/genética , Citocinas/genética , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Expressão Gênica/efeitos dos fármacos , Perfilação da Expressão Gênica , Humanos , Interleucinas/biossíntese , Interleucinas/genética , Análise de Sequência com Séries de Oligonucleotídeos , Farmacogenética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos
15.
Hum Biol ; 81(5-6): 899-909, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20504205

RESUMO

Human mannose- binding lectin (MBL) plays an important role in innate immunity. MBL deficiency is associated with mutations in the promoter region and in exon 1 of the MBL2 gene. Such deficiency has been correlated with elevated incidence of infections in infancy and in immunocompromised adults. We determined the distribution profile of the MBL2 gene variants in the general population of Benin (West Africa) and in a vulnerable subset of children with sickle cell disease (SCD) (SS homozygotes). Five hundred forty-two healthy individuals (274 newborns, 268 adults) and 128 patients with SCD (35 newborns, 93 children) were screened for the common variant alleles in the MBL2 secretor haplotype region (exon 1 and promoter). The p.G57E variant allele was the most frequent allele compared to p.G54D (27.5% vs. 1.6%, respectively). The p.R52C allele was not found in this population. There was no difference in allele or genotype frequencies between healthy newborns and newborns with SCD. Alleles associated with MBL deficiency were more frequent in adults than in newborns (69.8% vs. 57.3%, respectively; p=0.002). This enrichment was exclusively due to an elevated proportion of heterozygotes for the p.G57E allele (47.0% vs. 35.3%,respectively; p=0.004), supporting a potential selective advantage of this genotype. Our results, compared to those reported in other African countries, support the implication of the MBL2 gene in various major infections in Africa, such as meningitis and tuberculosis in HIV- positive patients.


Assuntos
Anemia Falciforme/genética , Variação Genética , Infecções por HIV/genética , Heterozigoto , Lectina de Ligação a Manose/genética , Adolescente , Adulto , África/epidemiologia , Anemia Falciforme/epidemiologia , Anemia Falciforme/história , Criança , Pré-Escolar , Feminino , Genética Populacional , Infecções por HIV/epidemiologia , Infecções por HIV/história , História do Século XXI , Humanos , Incidência , Lactente , Masculino , Pessoa de Meia-Idade , Mutação , Prevalência , Fatores de Risco , Adulto Jovem
16.
Blood Adv ; 3(15): 2328-2336, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31391165

RESUMO

Spleen dysfunction is central to morbidity and mortality in children with sickle cell anemia (SCA). The initiation and determinants of spleen injury, including acute splenic sequestration (ASS) have not been established. We investigated splenic function longitudinally in a cohort of 57 infants with SCA enrolled at 3 to 6 months of age and followed up to 24 months of age and explored the respective contribution of decreased red blood cell (RBC) deformability and increased RBC adhesion on splenic injury, including ASS. Spleen function was evaluated by sequential 99mTc heated RBC spleen scintigraphy and high-throughput quantification of RBCs with Howell-Jolly bodies (HJBs). At 6 and 18 months of age, spleen filtration function was decreased in 32% and 50% of infants, respectively, whereas the median %HJB-RBCs rose significantly (from 0.3% to 0.74%). An excellent correlation was established between %HJB-RBCs and spleen scintigraphy results. RBC adhesion to laminin and endothelial cells increased with time. Adhesion to endothelial cells negatively correlated with splenic function. Irreversibly sickled cells (ISCs), used as a surrogate marker of impaired deformability, were detected at enrollment and increased significantly at 18 months. %ISCs correlated positively with %HJB-RBCs and negatively with splenic uptake, indicating a relationship between their presence in the circulation and spleen dysfunction. In the subgroup of 8 infants who subsequently experienced ASS, %ISCs at enrollment were significantly higher compared with the asymptomatic group, suggesting a major role of impaired deformability in ASS. Higher levels of %HJB-RBCs were observed after the occurrence of ASS, demonstrating its negative impact on splenic function.


Assuntos
Anemia Falciforme/complicações , Suscetibilidade a Doenças , Esplenopatias/diagnóstico , Esplenopatias/etiologia , Biomarcadores , Deformação Eritrocítica/efeitos dos fármacos , Inclusões Eritrocíticas/patologia , Feminino , Humanos , Imunofenotipagem , Incidência , Masculino , Fosforilação , Cintilografia/métodos , Esplenopatias/epidemiologia
17.
Haematologica ; 93(4): 502-10, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18322255

RESUMO

BACKGROUND: We investigated adhesion receptor levels on red blood cells, reticulocytes and erythroid progenitors from children with sickle cell disease treated or not with hydroxyurea. DESIGN AND METHODS: Four groups of patients were investigated: (i) children receiving hydroxyurea for severe vaso-occlusive events (n=26); (ii) untreated children with a history of vaso-occlusive events (n=20); (iii) children with no history of vaso-occlusive events (n=28); and (iv) healthy African controls (n=27). Expression of adhesion receptors was analyzed by flow cytometry with specific mono-clonal antibodies. RESULTS: Reticulocytes and/or red blood cells from the children with sickle cell disease showed significantly higher expression of CD36, alpha 4beta 1, Lu/BCAM than those from controls, whatever the severity of the disease, as well as less marked increases in expression of ICAM-4, CD47 and CD147. Under hydroxyurea treatment, the expression of CD36, alpha 4beta 1 and ICAM-4 (to a lesser extent) was decreased, but surprisingly the expression of Lu/BCAM (and also CD47 and CD147 to a lesser extent) was significantly increased. Alterations of levels of adhesion receptors could be recapitulated in two-phase liquid cultures of erythroid progenitors from controls and untreated children with a history of vaso-occlusive disease, grown in the absence or presence of hydroxyurea. CONCLUSIONS: Our results suggest that hydroxyurea acts during erythroid development and modulates adhesion receptor expression and function differently, possibly by acting on gene expression and the signaling cascade leading to receptor activation.


Assuntos
Anemia Falciforme/tratamento farmacológico , Arteriopatias Oclusivas/etiologia , Moléculas de Adesão Celular/sangue , Adesão Celular/efeitos dos fármacos , Agregação Eritrocítica/efeitos dos fármacos , Hidroxiureia/uso terapêutico , Glicoproteínas de Membrana/sangue , Receptores Imunológicos/sangue , África Subsaariana/etnologia , Anemia Falciforme/sangue , Anemia Falciforme/complicações , Arteriopatias Oclusivas/tratamento farmacológico , Arteriopatias Oclusivas/metabolismo , Basigina/metabolismo , Antígenos CD36/metabolismo , Antígeno CD47/metabolismo , Moléculas de Adesão Celular/metabolismo , Criança , Eritrócitos/química , Células Precursoras Eritroides/química , Eritropoese/efeitos dos fármacos , Seguimentos , França , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Hidroxiureia/farmacologia , Integrina alfa4beta1/metabolismo , Sistema do Grupo Sanguíneo Lutheran , Proteínas de Neoplasias/metabolismo , Reticulócitos/química , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico , Transdução de Sinais/efeitos dos fármacos
18.
Eur J Haematol ; 80(4): 299-302, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18194479

RESUMO

Busulfan-mediated endothelial damage is believed to be a common mechanism in a variety of vascular disorders that occur during haematopoietic stem cell transplantation. The alkylating capacity of busulfan is compromised in vivo by enzymatic conjugation with glutathione, principally catalysed by glutathione S-transferase alpha (GST alpha). We investigated whether the susceptibility of endothelial cells to busulfan-mediated damage is related to their intrinsic deficiency in GST alpha expression. We tested for the expression of GST alpha mRNA by real-time quantitative PCR and the GST protein by enzyme-linked immunosorbent assay in various independently derived endothelial cell types (human bone marrow-derived endothelial cell line and endothelial cells from human vein umbilical cord ) and in a control hepatic cell line, HepG2. We demonstrate that endothelial cells, contrary to hepatic cells do not express GST alpha either at mRNA or protein levels and hence are potentially susceptible to busulfan-mediated cytotoxic damage.


Assuntos
Bussulfano/farmacologia , Células Endoteliais/efeitos dos fármacos , Transplante de Células-Tronco Hematopoéticas , Células Cultivadas , Células Endoteliais/metabolismo , Genótipo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Humanos , Regiões Promotoras Genéticas/genética
19.
Lab Chip ; 18(19): 2975-2984, 2018 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-30168832

RESUMO

The human red blood cell is a biconcave disc of 6-8 × 2 µm that is highly elastic. This capacity to deform enables it to stretch while circulating through narrow capillaries to ensure its main function of gas exchange. Red cell shape and deformability are altered in membrane disorders because of defects in skeletal or membrane proteins affecting protein-protein interactions. Red cell properties are also altered in other pathologies such as sickle cell disease. Sickle cell disease is a genetic hereditary disorder caused by a single point mutation in the ß-globin gene generating sickle haemoglobin (HbS). Hypoxia drives HbS polymerisation that is responsible for red cell sickling and reduced deformability. The main clinical features of sickle cell disease are vaso-occlusive crises and haemolytic anaemia. Foetal haemoglobin (HbF) inhibits HbS polymerisation and positively impacts red cell survival in the circulation but the mechanism through which it exerts this action is not fully characterized. In this study, we designed a microfluidic biochip mimicking the dimensions of human capillaries to measure the impact of repeated mechanical stress on the survival of red cells at the single cell scale under controlled pressure. We show that mechanical stress is a critical parameter underlying intravascular haemolysis in sickle cell disease and that high intracellular levels of HbF protect against lysis. The biochip is a promising tool to address red cell deformability in pathological situations and to screen for molecules positively impacting this parameter in order to improve red cell survival in the circulation.


Assuntos
Anemia Falciforme/sangue , Eritrócitos/patologia , Dispositivos Lab-On-A-Chip , Estresse Mecânico , Adolescente , Adulto , Fenômenos Biomecânicos , Criança , Pré-Escolar , Deformação Eritrocítica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
Haematologica ; 90(3): 401-3, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15749673

RESUMO

Plasma endothelin-1 (ET-1) is elevated in patients with sickle cell disease (SCD). Hydroxyurea (HU) is the only drug with demonstrated clinical efficacy in SCD. Here we show that treatment with HU results in a decreased concentration of circulating ET-1 which is not correlated with the HU-induced increase in HbF level. Blunting of the ET-1 vasoconstrictive stimulus could contribute to the beneficial effects of HU.


Assuntos
Anemia Falciforme/tratamento farmacológico , Endotelina-1/sangue , Hidroxiureia/uso terapêutico , Anemia Falciforme/sangue , Estudos de Casos e Controles , Criança , Hemoglobina Fetal/análise , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA