Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Sickle cell disease (SCD) is an autosomal recessive disorder affecting over 70,000 people in the United States. Following deoxygenation, red blood cells become deformed and appear in the characteristic sickle-shape. This change in protein structure leads to vasa-occlusive episodes, which may result in a variety of clinical manifestation including, but not limited to, painful crisis, stroke, acute chest syndrome, and/or splenic infarct. Due to the diversity of symptoms, management of this disease can be complex.In SCD, some of the treatment modalities involve controlling infections, pain management, fetal hemoglobin stimulation, blood transfusion, hematopoietic stem cell transplant and potentially gene therapy. This paper discusses the risk and benefits of these different treatment modalities. / 2999-01-01

Orientador: Nicola Amanda Conran Zorzetto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T04:12:18Z (GMT). No. of bitstreams: 1 Almeida_CamilaBononide_M.pdf: 1751160 bytes, checksum: 34725ba06e7511a0cd3632322e61fd59 (MD5) Previous issue date: 2006 / Resumo: A anemia falciforme é um distúrbio genético causado por uma mutação de ponto (Ácido Glutâmico-Valina) que produz uma hemoglobina S. Esta, quando desoxigenada, polimeriza causando deformação dos eritrócitos que se agregam às paredes da micro circulação culminando em crises vaso-oclusivas. Existem algumas moléculas de adesão que colaboram no bloqueio da circulação aderindo eritrócitos, células brancas e plaquetas à parede dos túbulos sanguíneos. A hidroxiuréia (HU) vem sendo utilizada no tratamento da doença devido à sua habilidade em aumentar a produção de hemoglobina fetal (HbF). No entanto, nem todos os pacientes respondem positivamente ao tratamento com HU. Estudos mostram que a HU quando degradada, produz óxido nítrico (NO), o qual ativa a enzima guanilato ciclase solúvel (GCs). Esta, por sua vez, transforma GTP em GMPc que atua como segundo mensageiro ativando provavelmente a transcrição do gene ?-globina aumentando assim, a concentração de HbF e melhorando o quadro clínico dos pacientes com essa doença. Por isso, o NO tornou-se fonte de grandes estudos, uma vez que é um importante vasodilatador. O objetivo desse trabalho foi elucidar qual família de fosfodiesterase (PDE) atua na degradação do GMPc das células de linhagem eritróide e se as drogas inibidoras dessas PDEs seriam capazes de aumentar a produção de ?-globina e conseqüentemente HbF em células eritróides de cultura. Para isso foram realizadas culturas de células K562 tratadas com diferentes drogas inibidoras de PDE (vinpocetina, sildenafil, dipiridamol e zaprinast) e com estimulador de guanilato ciclase, BAY41-2272. Observamos que os níveis de GMPc aumentaram principalmente nas células tratadas com 10µg/ml de dipiridamol e em alguns pontos de coletas com 10 e 50µM de vinpocetina. O mesmo não foi observado nas células tratadas com sildenafil e zaprinast. No entanto, todas as células tratadas com as diferentes concentrações de BAY41-2272 apresentaram aumento na concentração de GMPc. Com relação à expressão gênica relativa de ?-globina, observamos que as drogas dipiridamol, vinpocetina, sildenafil e zaprinast não foram capazes de provocar um aumento da expressão. Diferentemente, BAY41-2272 estimulou um aumento da expressão de ?-globina nas células K562 tratadas com 60 e 300nM após 48 horas de cultura. Além disso, estudamos a expressão das PDEs 1, 5 e 9 em células hematopoéticas e diferentes tecidos. Observamos que PDE9 é significativamente mais expressa em células K562, reticulócitos e neutrófilos. Além disso, observamos também que a expressão dessa PDE é significativamente maior nos reticulócitos e neutrófilos de paciente com anemia falciforme. Já naqueles que se encontravam sob terapia com HU, a expressão da PDE9 nos reticulócitos reverteu aos níveis do controle diferentemente dos neutrófilos, cuja expressão de PDE9 não se alterou entre os pacientes com ou sem terapia com HU. A expressão da PDE9 em outros tecidos (T98G, cólon, ovário, mama, fígado, pele, baço, testículo, útero e linfonodo) é significativamente menor do que nestas células hematopoéticas. Assim sendo, como aumento nos níveis celulares de GMPc pode ser importante tanto para a produção de HbF em células eritróides como para inibir a adesão de leucócitos, bloquear a ação da PDE9 pode representar uma nova estratégica célula-especifica para o tratamento da anemia falciforme / Abstract: Sickle cell disease (SCD) is a systemic disease with a multifaceted pathophysiology; the polymerisation of the sickle haemoglobin molecule (HbS), when deoxygenated, has many consequences that include haemolysis, inflammation, dysregulated nitric oxide (NO) homeostasis and oxidative abnormalities. Agents, such as hydroxyurea (HU), that increase levels of fetal hemoglobin (HbF), with consequent inhibition of HbS polymerization, and that may counteract other aspects of the disease's pathophysiology characterize important therapies for the disorder. Whilst HU therapy successfully augments HbF levels in many patients, not all patients respond to treatment. Studies demonstrate that HU, when degraded, produces nitric oxide (NO), in turn activating the enzyme, soluble guanylate cyclase (GC) in erythroid lineage cells. GC converts GTP to cGMP, which acts as a second messenger for NO, possibly activating the transcription of the ?-globin gene and, consequently, increasing the concentration of HbF. Due to evidence that NO bioavailability may be decreased in SCD individuals, recent research into SCD has focused on the role of NO in the disease, particularly since this gas is an important vasodilator. The objective of this study was to investigate which family(ies) of phosphodiesterases (PDE) may mediate the degradation of cGMP in erythroid lineage cells and whether drugs that inhibit these PDEs are capable of augmenting the production of ?-globin and, consequently, HbF in erythroid cells in culture. For this, cultures of K562 erythroleukemic cells were treated with different PDE inhibitors; vinpocetine, sildenafil citrate, dipyridamole and zaprinast. In addition, cultures were also treated with the guanylate cyclase stimulator, BAY41-2272. Increased levels of cGMP were observed principally in cells treated with 10µg/ml dipyridamole and at some time-points in the presence of 10 and 50µM vinpocetine. No changes in cGMP levels were observed in cells treated with sildenafil nor with zaprinast. However, cells treated with BAY 41-2272 demonstrated augmented cGMP levels at all concentrations used. With regard to relative ?-globin gene expression, dipyridamole, vinpocetine, sildenafil and zaprinast did not increase ?-globin gene expression; in contrast, BAY 41-2272 (60 and 300nM) stimulated increased ?-globin expression after 48h of culture. The gene expressions of PDEs 1, 5 and 9 were also studied in different hematopoietic cell types and other tissues. PDE9 is expressed, at significantly higher levels, in K562 cells (erythroleukemic cells), reticulocytes and neutrophils than in numerous other cell types tested (T98G, colon, mammary, ovary, testicle, liver, skin, spleen, uterus, limphonode). Furthermore, the expression of this PDE was even higher in the reticulocytes and neutrophils of patients with SCD. In patients on HU therapy, the expression of PDE9 in reticulocytes was reversed back to levels similar to those seen in controls. In contrast, PDE9 expression in neutrophils was similar in patients on or of HU therapy. Thus, since the increase in intracellular levels of cGMP may be important for the production of HbF in erythroid cells and also to inhibit leukocyte adhesion, the inhibition of the action of PDE9 may represent a novel drug target for cell-specific treatment of SCD / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Acute and chronic pain is a common hallmark of sickle cell disease (SCD) in children and adolescents, which can have a profound effect on their quality of life (QOL). However, this relationship is not well quantified. The purpose of this quantitative study was to examine the relationship between SCD pain burden and QOL among Black children ages 8-17 in Mississippi with SCD. The secondary aim was to compare children and caregiver reports of SCD pain burden and QOL with SCD. The social ecological model was used to identify personal factors that influence SCD pain burden and QOL of children with SCD. Eighty-five children and caregiver pairs completed paper surveys on demographics, pain burden, and QOL. Hierarchical linear regression results indicated that increased child SCD pain burden was statistically associated with decreased child's QOL (P

Sickle cell disease is a hereditary blood disorder caused by a point mutation in the gene encoding hemoglobin. This mutation causes hemoglobin molecules to polymerize during de-oxygenation of erythrocytes producing rod-shaped polymers that bend and distort the red blood cell membrane, making it more rigid and “sickled”. This sickling causes red blood cells to lose their flexibility and ability to navigate small capillaries and also enhances the production of pro-inflammatory membrane-derived microparticles, leading to chronic inflammation and many complications such as peripheral artery disease, stroke, myocardial infarction, vasculitis and even death. Sphingolipids are a class of lipids containing a backbone of sphingoid bases and are integral components of erythrocyte and microparticle membranes. Many of these lipids are known to mediate biological processes, but their expression, distribution and orientation in erythrocytes during sickle cell disease has never been explored. Sphingomyelin, the most abundant sphingolipid in the red blood cell membrane is hydrolyzed by sphingomyelinase to produce ceramide, which has been shown to alter membrane dynamics and enhance microvessel formation. Additionally, ceramide can be further metabolized to form sphingosine and sphingosine 1-phosphate, which is a bioactive ligand for 5 known G-protein coupled receptors present on most blood and vascular cells that modulates cell motility, proliferation, migration and phenotype. Prior to this work, it was not understood how sphingolipid metabolism contributes to vascular inflammation in sickle cell disease. Together, this body of work has elucidated key enzymatic and lipidomic alterations in sphingolipid metabolism (i.e. the activation of acid sphingomyelinase on red blood cells) that result in the production of sphingolipid-rich erythrocyte-derived microparticles, which enhance inflammatory cell activation. Our work has elucidated novel pharmacological targets to reduce microparticle generation and subsequent vascular inflammation in sickle cell disease.

According to the national survey of genetic blood disorders, the prevalence of haemoglobinopathies in Oman is 9.5% with Sickle Cell Disease (SCD) and Sickle Cell Trait (SCT) representing two major public health concerns and having great impact on individuals’ lives as well as on society (Al-Riyami et al., 2001). Complications related to SCD arise owing to ischemic tissue injury and may result in organ dysfunction and premature death. Patients with SCD often experience painful crises (vaso-occlusion), renal disease, acute chest syndrome (ACS) and other lifethreatening conditions. Physical education teachers tend to exclude children with SCD from PE classes due to their health status. It is currently unknown whether exercise might have beneficial, adverse or no effect in children and adults with SCD. Consequently, the recommendation of exercise for children and adults with SCD is rare. accordingly, there were three objectives to the work within this thesis: First, to investigate physical fitness markers in SCD and SCT and compare them to normal healthy children. With no reference data available, the aim of the first study was to provide a general idea of this population’s physical fitness parameters. The results suggest that children with SCT had similar anthropometric measurements, physical fitness and exercise responses to normal healthy children. In contrast, SCD children who were shorter and had lower body mass, higher fat mass and lower physical fitness than SCT and normal healthy children. In addition, children with SCD exhibited higher heart 3 rate and blood lactate responses in response to exercise than SCT children and normal healthy children. The second study was designed to determine cardiovascular responses to exercise in children with SCD and SCT and to compare them with those of normal healthy children from the same age ranges. Normal healthy children had a significantly higher estimated maximal oxygen uptake (VO2max) than SCT and SCD children (P < 0.05), with SCD children achieving the lowest VO2max. The mean heart rate in SCD and SCT was significantly higher during sub-maximal exercise than in normal healthy children (P < 0.05). White blood cell (WBC) count was also higher (P < 0.05) in the SCD group than in the other two groups, which is suggestive of a chronic inflammatory state. The third study aimed to determine whether a single bout of exercise elicits changes in interleukin- 6 (IL-6) concentrations in children with SCD. Children with SCD exhibited higher baseline IL-6 concentrations than the normal healthy children (P < 0.05), suggesting a persistent inflammatory state. However, the exercise bout did not elicit a significant change in IL-6 concentrations in either normal healthy or SCD children. The final study investigated the effect of an acute bout of exercise on postprandial changes in triacylglycerides (TAG), glucose, insulin and total cholesterol. Postprandial TAG concentrations were reduced in the exercise trial (P < 0.05). The postprandial glucose and insulin responses were also reduced in the exercise trial (P < 0.05). In conclusion, the work in this thesis suggests that Omani children with SCD have lower physical fitness than normal healthy children, and that exercise might have beneficial effects on this population. The lower physical fitness of SCD children is associated with altered body composition and lower oxygen-carrying capacity of the blood, as these children had shorter stature, lower body mass, higher fat mass and exhibited lower VO2max. The potential benefit of exercise for this population is demonstrated by the alterations of postprandial lipaemia after an acute bout of exercise. Higher TAG has been associated with increased incidence of vaso-occlusive events in subjects with SCD, and exercise lowered postprandial TAG concentrations in children with SCD.

Sickle cell disease (SCD) is a disorder in which defective hemoglobin causes sickling of red blood cells, inducing painful vaso-occlusive crises when blood flow is blocked at sites of red blood cell (RBC) clotting that can ultimately result in organ failure or death. This work demonstrates that sphingolipid metabolism is dysregulated in SCD and that this pathway can be targeted pharmacologically to prevent vaso-occlusion. We suggest a pathway in which the sickling of RBCs in SCD activates acid sphingomyelinase, altering the distribution and concentration of sphingolipids in the RBC membrane and resulting in the production of sphingolipid-rich microparticles that are secreted and can interact with cells in circulation. Sphingosine-1-phosphate (S1P) is believed to be a key modulator of SCD because it is stored at high concentrations in RBCs. Sphingolipid metabolism was confirmed to be dysregulated in SCD; most notably, S1P was significantly elevated in RBCs, and plasma, and microparticles, and the activity of acid sphingomyelinase and concentration of its byproduct, microparticles, were significantly elevated in SCD RBCs. Treatment of monocytes with S1P and SCD RBCs increased their adhesion over four-fold to endothelial cells, indicating that altered sphingolipid distribution in RBCs may contribute to vaso-occlusion through increasing myeloid cell adhesion. A cytokine profile of macrophages treated with SCD microparticles suggest that microparticles play a role in this process by increasing the secretion of inflammatory cytokines associated with SCD crises, including MIP-1α, IL-6, and TNF-α. Pilot in vitro studies in RBCs and in vivo studies in mice implicate that drugs targeting the sphingolipid metabolic pathway may be more effective treatment options than blood transfusions in managing SCD and preventing vaso-occlusive crises.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A anemia falciforme (AF) se caracteriza por anemia hemolÃtica crÃnica e com fenÃmenos vaso-oclusivos, seguidos de lesÃes a ÃrgÃos alvos, responsÃveis pela mortalidade associada a esta doenÃa. O fenÃmeno vaso-oclusivo està associado ao processo inflamatÃrio desencadeado pela polimerizaÃÃo da HbS desoxigenada, favorecendo a impactaÃÃo das hemÃcias na microcirculaÃÃo e subseqÃente obstruÃÃo da luz do endotÃlio. Numerosas evidÃncias sugerem que a reduÃÃo da biodisponibilidade do Ãxido nÃtrico (NO) pode ser um fator que favoreÃa a vaso-oclusÃo e que os radicais livres formados induzem à peroxidaÃÃo lipÃdica e à subseqÃente produÃÃo de quantidades anormais de malonaldeÃdo (MDA), que provoca alteraÃÃo da permeabilidade da membrana eritrocitÃria. Dentre os fatores genÃticos que modulam a clÃnica da AF consta os nÃveis de HbF. A hidroxiurÃia (HU) à utilizada no tratamento da AF e alÃm de aumentar os nÃveis de HbF parece contribuir como um doador de Ãxido nÃtrico. Nesse contexto, os objetivos do presente trabalho foram avaliar o estresse oxidativo por meio da dosagem sÃrica de MDA e determinar os nÃveis de NO e de lactato desidrogenase lÃctica (LDH) em pacientes com AF em acompanhamento ambulatorial no Hospital UniversitÃrio Walter CantÃdeo (HUWC) e correlacionar com o uso da HU. Desta forma foram utilizadas 65 amostras de sangue perifÃrico de pacientes adultos com AF em uso ou nÃo de HU, e um grupo controle foi elaborado por 20 doadores do banco de sangue com HbAA. Os nÃveis de NO, MDA e LDH foram determinados por mÃtodos bioquÃmicos. Os participantes da pesquisa foram selecionados junto ao centro de hematologia e hemoterapia do Cearà (HEMOCE). Todos os indivÃduos assinaram o termo de consentimento livre e esclarecido (TCLE) e foram submetidos a um questionÃrio prÃ-estruturado. Os dados obtidos foram expressos como mÃdias &#61617; desvio padrÃo e analisados utilizando-se o programa estatÃstico SPSS&#61650;15.0, utilizamos os coeficientes de correlaÃÃo de Pearsaon e de Spearman para o estudo das correlaÃÃes entre MDA, NO, LDH, HbF e Hb. Para comparar os trÃs grupos atravÃs dos nÃveis de MDA, NO e LDH obtemos os resultados atravÃs da anÃlise de deviance (ANODEV). verificamos um predomÃnio do sexo feminino, e das raÃas parda (grupo I) e negra (grupo II), sendo a grande maioria desses pacientes com idade variando de 20 a 35 anos (grupo I) e 20 a 40 anos (grupo II) e procedentes do estado de CearÃ. Em sua maioria, nÃo faziam uso de fumoetilismo e de suplementaÃÃo de vitaminas (C e E). Os nÃveis de MDA nos trÃs grupos sÃo todos diferentes, isto Ã, o grupo controle apresentou um nÃvel mÃdio de MDA superior ao grupo II, e este por sua vez superior ao grupo I. NÃo encontramos diferenÃa nos nÃveis sÃricos de NO em relaÃÃo ao uso de HU. Nos trÃs grupos observamos que apenas o grupo controle difere, apresentando uma mÃdia bem inferior a dos dois grupos de pacientes quanto aos nÃveis de LDH. Observamos uma correlaÃÃo inversamente proporcional entre os de nÃveis NO e de HbF para o grupo I, enquanto que para o grupo II nÃo houve correlaÃÃo. Em relaÃÃo à concentraÃÃo da Hb nÃo houve correlaÃÃo tanto no grupo I quanto no grupo II, com os nÃveis de NO. NÃo houve correlaÃÃo significativa entre os nÃveis de MDA e Hb e HbF para nenhum dos grupos estudados. Encontramos uma correlaÃÃo inversamente proporcional entre os nÃveis de LDH e de Hb para o grupo I. Observou-se nÃveis elevados de MDA em pacientes do grupo II que realizaram duas ou mais transfusÃes no decorrer do ano, que apresentaram Ãlcera de perna maleolar e que tiveram trÃs ou mais crises vaso-oclusivas para ambos os grupos. NÃo encontramos nenhuma relaÃÃo do NO com as variÃveis clÃnicas. CONCLUSÃO: Nossos resultados mostram que os paciente em uso de HU nÃo estÃo protegidos contra a peroxidaÃÃo lipÃdica, hemÃlise quanto ao consumo de NO disponÃvel. / The sickle-cell disease (SCD) is characterized by hemolytic chronic anemia and with vase-occlusive phenomena, followed by target organs which are responsible for the mortality associated with this disease. The vase-occlusive phenomenon is associated with the inflammatory process unleashed by the polymerization of deoxygenated HbS, which favors the polymerization of erythrocytes in the microcirculation and the subsequent obstruction of endothelia light. Several evidences suggest that the reduction of the bioavailability of the nitric oxide (NO) can be a factor to favor the vase-occlusion and that the free radicals produced give rise to the lipidic peroxidation and the subsequent production of the abnormal quantities of malonaldehyde (MDA), which induce the permeability of the red cell membrane. Among the genetic factors that modulate the clinic of the AF, there is the HbF levels. The hydroxyurea (HU) is used in the treatment of SCD and apart from increasing the HbF levels it also seems to contribute as a nitric oxide donator. In this context, the present work aims to evaluate the oxidative stress by means of seric dosage of the MDA and to determinate the levels of NO and lactate desidogenase lactica (LDH) in patients with SCD by means within the Walter CantÃdeo University Hospital (HUWC) and to correlate with the use of HU. This way, it was used 65 samples of peripheral blood of adult patients with AF with either HU or not, and a control group was composed by 20 donors of the blood bank with HbAA. The levels of NO, MDA and LDH were determined by biochemical methods. The participants of the research were selected in the Center of Hematology and Hemotherapy of Cearà State (HEMOCE). All the participants have signed a document stating free consent and approval (TCLE) and they were submitted to a previously elaborated questionnaire. The obtained data were expressed as averages  pattern deviation and analyzed by using a statistics software SPSS&#61650;15.0, using Pearson and Spearman correlation coefficients for the study of the correlations among MDA, NO, LDH, HbF and Hb. In order to compare the three groups through the levels of MDA, NO and LDH, the results were obtained by means of deviance analysis (ANODEV). It has been observed a majority of females and fallow race (group I) and black (group II), in which the most part of these patients have ages in the range of 20-35 (group I) and 20-40 (group II) and come from Cearà State. Most of them did not smoke, drink alcohol nor use vitamin supplements (C and E). The levels of MDA in the three groups are all different, i. e., the control group showed an average level of MDA higher than group II, and the later higher than that of the group one. It was not verified difference in the seric levels of NO in relation to the use of HU. In the three groups, it was observed that only the control group is different, showing an average much lower than those of the other two groups of patients regarding the levels of LDH. It was also observed a correlation inversely proportional between the two levels of NO and HbF for the group I, while in the group II there was no correlation. Regarding to the concentration of Hb, there was no correlation both in the group I and in the group II, with levels of NO. There was no significantly correlation among the levels of MDA, Hb and HbF for the studied groups. It was found a correlation inversely proportional between the levels of LDH and Hb for the group I. It was observed accentuated levels of MDA in patients of group II who have made two or more transfusions throughout the year, who had leg ulcers and who had three or more vase-occlusive crises form both the groups. It was found no relation of NO with the clinic variables. CONCLUSÃO: Our results have shown that patients who use HU are not protected against lipidic peroxidation, hemolysis and consume of available NO

Sickle cell disease (SCD) is a chronic, lifelong, often debilitating, inherited disorder that can affect every organ system. Affected individuals often experience repetitive pain crises, multiple hospitalizations and a diminished quality of life. Many people at risk for SCD are unaware of their sickle cell carrier status and surprisingly health care providers’ knowledge of SCD is limited. Research literature focuses mainly on management of clinical manifestations of the disease. This systematic review and integrative qualitative meta-synthesis aims to capture parents’ perspectives on the screening process and diagnosis of SCD or sickle cell trait (SCT). Information generated by this review will be helpful in contributing to the development or enhancement of guidelines and protocols in SCD and SCT management for health care providers and health care educators. / Thesis / Master of Science (MSc)

No description available.

Sickle cell disease (SCD) is one of the most difficult and stressful chronic diseases for parents of afflicted children to manage. Managing SCD can be traumatic for parents particularly if they have no specific coping strategies for managing the disease or ensuring the child visits the doctor as scheduled. The use of certain coping strategies may affect the parents' and patients' perceptions of the illness and influence their decisions regarding treatment, which can have a lasting impact on their lives. Effective parental strategies such as positive thinking can aid in disease management, but there is limited research on the coping strategies used by parents of children with SCD specifically. The purpose of this phenomenological study, which was guided by Thompson and Gustafson's transactional stress and coping model, was to describe parents' coping strategies in managing their young child's SCD as it relates to use of health services. Data collection included one-to-one, open-ended interviews with 10 parents of children with SCD. Colaizzi's method of phenomenological data analysis was used to identify themes. Five themes emerged from data analysis and they are: parental methods of coping with SCD, participants' understanding of SCD, SCD family and support, managing SCD with hydration and medication, and experience accessing healthcare. These results indicated the participants' coping strategies varied according to their individual situations. Insight from this study could lead to positive social change by helping to identify specific coping strategies parents can use to better manage their child's disease and effectively access available health services.