Orientador: Milton Artur Ruiz / Coorientador: Claudia Regina Bonini Domingos / Banca: Silma Maria Alves de Melo / Banca: Isabeth da Fonseca Estevão / Resumo: A anemia falciforme (AF) afeta milhões de pessoas em todo o mundo e está associada a altas taxas de morbidade e mortalidade. Apresenta uma série de manifestações fenotípicas, que são influenciadas por fatores genéticos e ambientais, resultando em fenótipos diversificados, e um tratamento bastante eficaz tem sido o uso de hidroxiureia (HU), que ameniza os sintomas e a necessidade de transfusão sanguínea e hospitalização. Estudos de associação de genomas já demonstraram que polimorfismos genéticos podem desempenhar influência no perfil clínico dos pacientes, assim como na resposta destes à medicação. Os polimofismos -308G/A no gene TNFA e -509C/T no gene TGFB aumentam a produção das suas respectivas citocinas que atuam principalmente em vias inflamatórias e são fortes candidatos a estarem envolvidos na ocorrência de episódios vaso-oclusivos característicos da doença. Dessa forma, o objetivo do trabalho foi verificar a frequência desses polimorfismos em portadores da AF, com e sem o uso de HU, e possível relação com a gravidade das manifestações clínicas da doença. Foram obtidas 588 amostras de sangue periférico de pacientes com doença falciforme em acompanhamento no HEMORIO. A partir destas, foram separados, aleatoriamente, 240 pacientes com AF, cujo genótipo foi confirmado por procedimentos laboratoriais clássicos e moleculares. Estes foram genotipados para os polimorfismos -308G/A (TNFA) e -509C/T (TGFB) por PCR-RFLP. Os dados hematológicos e clínicos parciais de 118, dos 240 pacientes, foram obtidos por questionário e consulta aos prontuários médicos e banco de dados. A frequência do polimorfismo -308G/A foi de 0,83 em homozigose e 17,92% em heterozigose. Para o polimorfismo -509C/T, foi de 6,25% e 48,33%, respectivamente. Não foi observada associação entre o polimorfismo -308G/A e as manifestações clínicas... (Resumo completo, clicar acesso eletrônico aba / Abstract: Sickle cell anemia (SCA) affects millions of people worldwide and is associated with high morbidity and mortality. This affection shows various phenotypic manifestations, which are influenced by genetic and environmental factors, resulting in many phenotypes, and the most effective treatment has been the use of hydroxyurea (HU), which improves the symptoms and the requirement for blood transfusion and hospitalization. Genome association studies have shown that genetic polymorphisms may play role on the clinical profile of patients, as well as in response to these medications. The -308G/A and -509C/T polymorphisms, in TNFA and TGFB genes respectively, increase production of their cytokines, which act on inflammatory pathways and are strong candidates to be involved in the occurrence of vaso-occlusive episodes. The aim of this study was to determine the frequency of these polymorphisms in patients with AF, with and without HU utilization, and possible relationship with the severity of clinical manifestations of disease. We obtained 588 peripheral blood samples of patients with sickle cell disease at HEMORIO. From these, were separated at random 240 patients with AF, whose genotype was confirmed by classical and molecular laboratory procedures. They were genotyped for polymorphisms-308G/A (TNFA) and-509C/T (TGFB) by PCR-RFLP. The hematological and clinical data of 118 of the 240 patients, were obtained by questionnaire and medical records and database. The frequency of polymorphism -308G/A was 0.83% in homozygous and 17.92% in heterozygous. For the polymorphism -509C/T, was 6,25% and 48.33% respectively. No association between polymorphism -308G/A and clinical manifestations in patients was found. Concerning the polymorphism-509C/T, the mutant allele (T) proved to be a risk... (Complete abstract click electronic access below) / Mestre

This research study was focused on two broad areas of exploration. The first area deals with the identification of various factors affecting a family when a family member has the anemia or symptomatic form of sickle cell disease. Data obtained from a personally administered questionnaire (Form A), enabled the researchers to determine if genetic counseling had been offered and received, and if this counseling was considered helpful by the respondents. In addition to this, data was collected on several demographic variables, including sex and age of patient, family income, religion, education, ethnic group, living arrangements and occupation, and response to and knowledge of sickle cell anemia.

Sickle cell trait (SCT), sickle cell disease’s carrier status, is a common genetic variant found in many people of African, South Asian, Middle Eastern and Mediterranean descent. While overall considered a benign carrier status, it has been associated with an increased risk of several diseases, including exertional rhabdomyolysis (ER), and chronic kidney disease. While epidemiological evidence links SCT with ER, the actual pathophysiological mechanism less understood. Additionally, while there is an increased prevalence of atrial fibrillation (AF) documented in people with sickle cell disease, studies in individuals with SCT are lacking. The objectives of this thesis are twofold: The first chapter is a literature review of studies to examine the physiological mechanisms linking SCT and exertional rhabdomyolysis. The second chapter is original research into the associations of SCT with AF. The first chapter reviews studies that identify aggravating factors that may promote ER. It then reviews observed pathophysiological changes in people with SCT that may increase the risk of ER. It summarizes studies that assess mitigating factors that decrease the risk of ER. It then presents a postulated pathway of mechanisms that associate SCT with ER. The second chapter uses data from African-American participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study to assess the association of SCT with prevalent AF (by electrocardiogram or medical history) using logistic regression models adjusting for age, sex, income, education, history of stroke, myocardial infarction, diabetes, hypertension, and chronic kidney disease. In 10,409 participants with baseline ECG data and genotyping, 778 (7.5%) had SCT and 811 (7.8%) had prevalent AF. After adjusting for age, sex, education and income, SCT was associated with AF, OR 1.32 (95% CI 1.03-1.70). SCT remained associated with prevalent AF after adjusting for potential factors on the causal pathway such as hypertension and chronic kidney disease suggesting alternate mechanisms for the increased risk. SCT was associated with a higher prevalence of AF and a non-significantly higher incident AF over a 9.2 year period independent of AF risk factors.

In this study we present feasibility of a mobile monitoring and reporting system that would provide an accurate unbiased screening tool to systematically analyze opioid adherence in Sickle cell disease patients. In addition, the software simultaneously measures pain. The Mobile Applications Rating Scale: a new and validated tool for assessing the quality of health mobile apps for engagement, functionality, aesthetics, information quality, subjective quality, relevance and overall impact was administered post usage to evaluate the application. A total of 28 patients were recruited to review and test the software at one sitting. The majority of the population found the application to be relevant for their care. Patients were also asked to report on the completeness of information within the app, the majority (96%) reported on the application’s completeness while 4% estimated the information to be minimal or overwhelming. The quality of information as it pertains to sickle cell patients was overwhelimingly reported to be relevant (91.7%); only 8.3% found the application to be poorly relevant to sickle cell disease. The application’s performance was positively rated while the ease of its use positively rated at 91.7%. Most participants (85.7%) found the application to be interesting to use while 74% found it entertaining. All users found the application’s navigation to be logical and accurate with consistent and intuitive gestural design. We conclude that surveyed patients believe it is feasible to use a smartphone application specifically targeted to monitor opioid use and behavior in patients with sickle cell disease (SCD)-associated pain

O avanço de novas tecnologias tem conduzido à geração de grandes volumes de dados biológicos, provenientes, por exemplo, de sequenciamento de genomas, expressão de genes e proteínas, estrutura de proteínas e RNAs, análise de imagens, formulários eletrônicos e exames médicos. Com o intuito de transformar esses volumosos conjuntos de dados brutos em informação e conhecimento que sejam compreensíveis e interpretáveis, técnicas de mineração de dados têm sido aplicadas no estudos de diversos processos biológicos, como a predição de genes, funções de genes, fenótipos, módulos regulatórios, estrutura de proteínas, função de proteínas e descoberta de interações moleculares. Cada conjunto de dados tem suas particularidades, demandando o emprego de distintas metodologias de análises e algoritmos de reconhecimento de padrões, como Florestas Aleatórias, Redes Neurais, Deep Learning, Modelo Oculto de Markov, Máquina de Vetores de Suporte, K-médias e Análise de Componentes Principais. A escolha do algoritmo a ser utilizado é influenciada por fatores como o tipo dos dados, a forma como são gerados, sua natureza, suas características e o objetivo do estudo. Assim, este trabalho teve como objetivo explorar técnicas de reconhecimento de padrões e estatística aplicadas a um conjunto de dados biológicos envolvendo pacientes com anemia falciforme, para extração de informação e conhecimento sobre os processos, fenômenos e sistemas biológicos envolvidos na doença. Foram realizadas análises de um conjunto de dados diverso, proveniente de registros clínicos, entrevistas com pacientes, exames clínicos e sequenciamento de polimorfismos de nucleotídeo único. Os dados demandam diferentes abordagens de análises, exploração e revelação da estrutura de dados intrínseca. Em uma análise inicial, foram aplicados algoritmos de reconhecimento de padrões a dados clínicos de pacientes com anemia falciforme, com o objetivo de obter grupos contendo pacientes similares. Os algoritmos PCAMix, PAM e TwoStep clustering foram capazes de gerar grupos homogêneos de pacientes, sendo que estes grupos apresentam distintas características clínicas e diferentes níveis de gravidade da doença quando comparados entre si. Os resultados indicam que características como idade, níveis de bilirrubina, histórico de transfusões, dor aguda da anemia falciforme, síndrome torácica aguda, acidente vascular cerebral, infarto cerebral silencioso, ataque isquêmico transitório, úlcera de pernas, moyamoya, ferritina, contagem de reti- culócitos, retinopatias, ataques epiléticos e hemossiderose transfusional são importantes para a definição de grupos homogêneos de pacientes, que apresentem distintos níveis de gravidade de anemia falciforme quando comparados entre si. Adicionalmente à análise de agrupamento, o conjunto de pacientes com histórico de priapismo, uma das complicações da anemia falciforme, foi estudado. O objetivo desta análise foi caracterizar clinicamente os pacientes com histórico de priapismo, e investigar fatores genéticos que alterassem o risco da doença. Observou-se que o priapismo ocorreu mais frequentemente em pacientes com genótipo HbSS, estando associado a idades mais avançadas e à ocorrência de hipertensão pulmonar e necrose avascular. Dois novos SNPs foram associados à ocorrência de priapismo, bem como houve indicativo de replicação da associação do gene TGFBR3 ao risco da doença. / Technology has been producing large biological datasets of genome sequences, gene and protein expression, RNA and protein structure, images, electronic questionnaires and laboratory test results. In order to extract information and knowledge from these large datasets, data mining techniques have been used in the investigation of a wide range of biological processes, with the goal of predicting gene, gene function, phenotype, regulatory modules, molecular interaction, protein function and protein structure. Each dataset has different characteristics and demands the application of different statistical methodologies and pattern recognition algorithms, such as Random Forests, Neural Networks, Deep Learning, Markov Hidden Model, Support Vector Machine, K-means and Principal Component Analysis. The choice of the algorithm depends on data type, data generation, data characteristics and goal of the study. Therefore, the goal of this work was to explore pattern recognition and statistical techniques in a biological dataset on sickle cell disease patients, in order to extract information and knowledge about the biological systems, processes and mechanisms associated with the disease. A diverse dataset was analyzed, containing data from medical records, patient interviews, laboratory tests and single nucleotide polymorphisms. The dataset requires a variety of analysis approaches, in order to explore and reveal the hidden data structure. In an initial investigation, pattern recognition algorithms were used in the analysis of clinical data from sickle cell patients, in order to obtain clusters containing similar patients. PCAMix, PAM and TwoStep clustering algorithms generated homogeneous clusters of patients that display different clinical characteristics and different levels of disease severity. The results show that age, bilirubin levels, transfusion history, vaso-occlusive pain episodes, acute chest syndrome, infarctive stroke, hemorrhagic stroke, ischemic attack, leg ulcers, moyamoya, ferritin, reticulocyte count, retinopathy, seizures and transfusional hemosiderosis are important to define homogeneous patient clusters, with distinct levels of sickle cell severity. Additionally, the patients with history of priapism, a sickle cell related complication, were studied. The goal of the study was to characterize patients with priapism history and investigate genetic factors that modify the risks of the disease. Priapism more frequently occurred among patients with HbSS genotype and was associated with older age and occurrence of pulmonary hypertension and avascular necrosis. Two novel SNPs were associated with priapism and there was evidence of replication of a previously reported association of TGFBR3 with priapism risk.

Linus Pauling incorporated hemoglobin and a disease of the blood, sickle cell anemia, into many of his researches between the mid-1930s and mid-1970s. In the early 1930s Pauling became interested in organic chemistry and named hemoglobin as one of the first biochemical substances that he planned to analyze. In 1935 he published his first paper on hemoglobin, which determined the structure of the four hemes in hemoglobin. Pauling continued to study the structure of hemoglobin until the early 1950s when he proposed that it was an alpha-helix. In 1945 Pauling learned about sickle cell anemia and published an important paper in 1949 with Harvey A. Itano, S.J. Singer, and Ibert C. Wells titled "Sickle Cell Anemia, a Molecular Disease." Pauling investigated hemoglobin into the mid-1970s when he tried to find an orthomolecular therapy for sickle cell anemia. From the mid-1950s to early 1970s, Pauling also used sickle cell anemia to promote negative eugenics, point out the possible mutagenic effects caused by nuclear weapons testing, and propose an evolutionary theory. Additionally, in the final year of his life, Pauling wrote two forewords for books on sickle cell anemia, which were published in 1994, the year he died. Hemoglobin and sickle cell anemia can be considered a theme within Pauling's work. He often returned to normal and abnormal hemoglobin as his primary substance for examination, and his familiarity with hemoglobin and sickle cell anemia inspired new research. / Graduation date: 2004

Nucleic acids are an emerging class of therapeutics with the capacity to repair both DNA and RNA mutations in clinically relevant targets. We have used two approaches, mobile group II introns and Spliceosome Mediated RNA Trans-splicing (SMaRT), to correct β-globin mutations at the DNA and RNA levels respectively. We show that the group II intron inserts site-specifically into its DNA target, even when similar targets are available. Experiments transitioning this therapeutic into mammalian cell systems are then described. We also illustrate how SMaRT RNA repair can be used to correct β-globin mutations involved in sickle cell disease and some forms of β- thalassemia. We uncovered diverse repair efficiencies when targeting sickle cell versus β- thalassemia transcripts in mammalian cells. Possible reasons for this and how it might direct target choice for the SMaRT therapeutic approach are both discussed. The therapeutic molecule in SMaRT, a Pre-Trans-splicing Molecule or PTM, is also delivered via lentivirus to erythrocyte precursors cultured from the peripheral blood of sickle cell patients. Preliminary results from these experiments are discussed. / Dissertation

Sickle cell anemia is a hematological disorder that is caused by a single point mutation in the beta-globin chain of hemoglobin. It results in several complications related to the small and large vessels in patients with the disease. Large vessel complications include cerebral infarcts, which are observed in children under ten years old. The mechanism behind this complication is not completely understood. It is the goal of this project to begin to understand the role sickle erythrocytes may play in causing endothelial dysfunction as a precursor to sickle related complications. The hypothesis of this work is that exposure of large vessel endothelium to sickle erythrocytes causes an increase in endothelial permeability through loosening of adherens junctions. In the first goal of this work, bovine aortic endothelial cells (BAECs) are grown on coverslips and exposed to sickle erythrocytes for 5 minutes and either immediately fixed or incubated in 30 minutes and then fixed. Immunofluorescent studies labeling VE cadherin show changes in VE cadherin dynamics, suggesting sickle erythrocytes may be involved in this observation. Next, BAECs were grown on transwell inserts and exposed to sickle erythrocytes for 5 minutes. The erythrocytes are washed off and the BAEC are incubated with 10,000 MW dextran conjugated to lucifer yellow or FITC-BSA or to determine BAEC permeability. When dextran is used as the test molecule, endothelial permeability did not show a significant change from baseline. However, when BSA is used as the test molecule, increases in endothelial permeability are observed. Explanations into the differences between the transport mechanisms of the two molecules are discussed. These experiments show changes in VE cadherin localization due to sickle erythrocyte exposure. This may cause increases in endothelial permeability and an experimental model and preliminary studies are performed. This study provides potential mechanisms to explain the changes in VE cadherin localization and provide suggestions for further studies to test the effect of sickle erythrocytes on endothelial permeability. This work provides a strong foundation for continuing studies on the effects of sickle erythrocytes on endothelial dysfunction within the confines of sickle related complications.

Thesis (M. S. in Psychology)--Vanderbilt University, May 2006. / Title from title screen. Includes bibliographical references.

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