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Nadja de Jesus G. dos Santos. Hemoglobina fetal...pdf: 2812470 bytes, checksum: 55476e9f2f10311274d9f1a3382fda56 (MD5) / Made available in DSpace on 2012-11-19T18:11:37Z (GMT). No. of bitstreams: 1
Nadja de Jesus G. dos Santos. Hemoglobina fetal...pdf: 2812470 bytes, checksum: 55476e9f2f10311274d9f1a3382fda56 (MD5)
Previous issue date: 2012 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil / O estudo de marcadores associados à síntese de hemoglobina fetal (HbF) é de grande interesse científico, pois contribui para o entendimento dos mecanismos regulatórios dos genes envolvidos na síntese das cadeias globínicas gama, uma vez que esta Hb é importante na modulação genética da anemia falciforme (HbSS). O objetivo desse estudo foi investigar a influência de alterações em genes envolvidos na síntese de HbF e suas associações com marcadores laboratoriais e clínicos na HbSS e caracterizar o fenótipo e o genótipo de indivíduos com o perfil sugestivo de persistência hereditária de hemoglobina fetal (PHHF). Dessa forma, foi realizado um estudo de corte transversal, seguido de caso-controle com a casuística de 43 indivíduos HbSS com HbF> 3,0% e 3 indivíduos com perfil sugestivo de PHHF. O presente estudo foi aprovado pelo CEP-CpGM-Fiocruz. Os polimorfismos HBG2 -396/-391del, HBG2 SNP -369 C>G, HBG2 -309 A>G, HBG2 -157 T>C, HBG1 -499 T>A, HBG1 -369 C>G, HBG1 -271 C>T e HBG1-225/-222del foram investigados por sequenciamento automático de DNA; os haplótipos ligados ao gene da globina beta foram investigados por PCR-RFLP; os polimorfismos BCL11Ars766432, BCL11Ars6732518, OR51B5/6rs4910756, OR51B5/6rs7483122, HMIPrs11759553, HMIPrs35959442 foram investigados por PCR em tempo real; a talassemia alfa 23.7 Kb e as deleções PHHF-1, PHHF-2 e PHHF-4 por PCR. As análises hematológicas foram realizadas em contador automático de células, o perfil de hemoglobina foi confirmado por cromatografia líquida de alto desempenho e as dosagens bioquímicas foram investigadas por quimiluminescência. As concentrações de HbF foram associadas com HbS (p<0,0001), hematócrito (p=0,035), VCM (p=0,010), HCM (p=0,045), colesterol VLDL (p=0,044), ferro (p=0,001) e ferritina (p=0,042). Os polimorfismos estudados apresentaram associação com marcadores laboratoriais e clínicos no grupo estudado. O polimorfismo HBG1 -271 C>T foi associado com a concentração de HbF (p=0,027; RP=4,45; IC95%= 1,14 – 17,41) e ferro (p=0,0076); o HBG1 -499 T>A com as concentrações de glicose (p=0,007) e de alfa-1 antitripsina (p=0,008); o HBG1 -225/-222del com as concentrações de colesterol LDL (p=0,017); o HBG2 -396/-391del com as concentrações de HbS (p=0,017), creatinina (p=0,042) e bilirrubina p=0,030), sendo associado também ao quadro clínico mais grave da doença, com ocorrência frequente de crises vaso-oclusivas (p=0,046), litíase biliar (p=0,021) e o uso de hemoterápicos (p=0,009); o BCL11A rs766432 com a contagem de reticulócitos (p<0,0001) e a concentração de colesterol total (p=0,033); o BCL11Ars6736518 com concentração de glicose (p=0,049) e a contagem de eosinófilos (p=0,012); o HMIPrs35959442 com as concentrações de ferritina (p=0,035), creatinina (p=0,008) e VCM (p=0,022); o HMIPrs11759553 com as concentrações de ácido úrico (p=0,033) e ferritina (p=0,020); e os polimorfismos OR51B5/6rs7483122 e OR51B5/6 rs4910756 com as concentrações de creatinina (p=0,001). A análise multivariada mostrou associação do genótipo CAR/CAR com a concentração diminuída de HbF e o uso de hemoterápicos. A talassemia alfa 23.7 Kb apresentou efeito protetor, sendo associada com as concentrações de ALT (p=0,044), AST (p=0,039) e com a contagem de linfócitos (p=0,050). Os três casos associados ao fenótipo de PHHF não apresentaram alterações clínicas e laboratoriais significativas, inclusive o caso 3, que apresentou o genótipo HbSF. É importante salientar que esses indivíduos não eram portadores de nenhuma das formas de PHHF investigadas. Estudos adicionais devem ser conduzidos com o objetivo de validar os resultados encontrados nesse estudo e de esclarecer os possíveis mecanismos pelos quais os marcadores moleculares investigados interferem na modulação da síntese de HbF e se esses biomarcadores podem apresentar mecanismos diferenciados daqueles comumente investigado, uma vez que foram descritas associações com marcadores importantes para o acompanhamento clínico de indivíduos HbSS. / The study of markers associated with the fetal hemoglobin (HbF) synthesis is of great scientific interest, since it can contribute to understanding regulatory mechanisms of genes involved in the synthesis of globin chains, once that HbF participate in the genetic modulation of sickle cell anemia (HbSS). The aim of this study was to investigate the influence of changes in genes involved in the synthesis of HbF and their associations with clinical and laboratory markers in HbSS and characterize the phenotype and genotype of individuals with the profile suggestive of hereditary persistence of fetal hemoglobin (HPFH). Thus, we performed a cross-sectional study, followed by a case-control, in a group of 43 HbSS individuals with HbF> 3.0% and 3 individuals with a suggestive profile of HPFH. Polymorphisms HBG2 -396/-391del, the HBG2 SNP -369 C> G, HBG2 -309 A> G, HBG2 -157 T> C, HBG1 -499 T> A, HBG1 -369 C> G HBG1 the -271 C> T and HBG1-225/-222del were investigated by automated DNA sequencing; haplotypes linked to the beta globin gene were investigated by PCR-RFLP; single nucleotide polymorphisms of BCL11Ars766432, BCL11Ars6732518, OR51B5/6rs4910756, OR51B5/6rs7483122 , HMIPrs11759553, HMIPrs35959442 were investigated by real-time PCR, alpha thalassemia 2 with 3.7 Kb deletion and HPFH-1 , HPFH-2 and HPFH-4 deletions by PCR Hematological tests were performed in automatic cell counter, the profile of hemoglobin was confirmed by high performance liquid chromatography and biochemical analysis were investigated by immunochemistry assay method. Levels of HbF were associated with HbS (p <0.0001), hematocrit (p= 0.035), MVC (p= 0.010), MHC (p= 0.045), VLDL cholesterol (p= 0.044), iron (p= 0.001) and ferritin (p= 0.042). Polymorphisms were associated with clinical and laboratory markers in the studied group. The polymorphism HBG1 -271 C>T was associated with the concentration of HbF (p = 0.027, PR = 4.45, 95% CI 1.14 - 17.41) and iron (p= 0.0076); the HBG1 - 499 T> A was associated with the level of glucose (p= 0.007) and alpha-1 antitrypsin (p= 0.008); the HBG1 -225/-222del with LDL cholesterol concentrations (p= 0.017); the HBG2 - 396/-391del with Hb concentrations (p= 0.017), creatinine (p= 0.042) and bilirubin (p= 0.030), and also with a more severe clinical disease, with frequent occurrence of vaso-occlusive crises (p= 0.046), gallstones (p= 0.021) and the use of haemotherapic (p= 0.009); the BCL11A rs766432 with the reticulocyte count (p<0.0001) and the concentration of total cholesterol (p= 0.033) and BCL11Ars6736518 with the level of glucose (p= 0.049) and eosinophil count (p= 0.012); the HMIPrs35959442 with ferritin concentrations (p= 0.035), creatinina (p= 0.008 ) and MCV (p= 0.022), the HMIPrs11759553 with concentrations of uric acid (p= 0.033) and ferritin (p= 0.020); and the polymorphisms OR51B5/6rs7483122 and the OR51B5/6rs4910756 with creatinine concentrations (p= 0.001 ). Multivariate analysis pointed for the association of the genotype CAR / CAR with a decrease in HbF concentration with the use of blood therapy. The alpha thalassemia 2 with 3.7 Kb deletion showed a protective effect, being associated with concentrations of ALT (p= 0.044), AST (p= 0.039) and lymphocyte count (p= 0.050). The three cases associated with HPFH phenotype did not show significant association with clinical and laboratory data, including the case 3, that showed the genotype HbSF. It is noteworthy that these individuals were not classified in any described HPFH type investigated. Further studies should be conducted in order to validate results found in this work and to clarify the possible mechanisms by which those investigated molecular markers can interfere with the modulation of the HbF synthesis and if they have mechanisms differentiate from the ones commonly investigated, once that the present study described association with important biomarkers that have been used for monitoring individuals with HbSS.
| Identifer | oai:union.ndltd.org:IBICT/oai:www.arca.fiocruz.br:icict/5830 |
| Date | January 2012 |
| Creators | Santos, Nadja de Jesus Gonçalves dos |
| Contributors | Bertuzzo, Carmen Silvia, Alcantara, Luiz Carlos Júnior, Gonçalves, Marilda de Souza, Gonçalves, Marilda de Souza |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da FIOCRUZ, instname:Fundação Oswaldo Cruz, instacron:FIOCRUZ |
| Rights | Nadja de Jesus Gonçalves dos Santos, info:eu-repo/semantics/openAccess |
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