INTRODUÇÃO: As Hemoglobinopatias podem ser divididas em Talassemias e Doença Falciforme (DF), mas do ponto de vista clínico, ambas apresentam um quadro de anemia hemolítica crônica, o que acarreta uma série de complicações, entre estas a Hipertensão Pulmonar (HP). Estima-se que cerca de 20-40% da população com DF/talassemia apresente HP, sendo que este diagnóstico está associado a uma elevada morbi-mortalidade. Poucos estudos avaliaram esta prevalência em crianças. O Objetivo deste estudo foi avaliar a prevalência desta complicação na população pediátrica, e associá-la com características clínicas e laboratoriais. MÉTODOS: Estudo de Corte Transversal, com avaliação de 45 pacientes com diagnóstico de DF ou Talassemia maior/ intermédia entre 3-18 anos, atendidos de forma consecutiva no ambulatório de Hemoglobinopatias do HCPA. Os pacientes foram submetidos a um ecocardiograma para estimativa da pressão sistólica da artéria pulmonar, sendo que foi considerado como tendo risco de HP os pacientes com velocidade de regurgitação tricúspide (VRT) ≥ 2,5m/s. Foram obtidos dados clínicos e laboratoriais para avaliação dos parâmetros hemolíticos, função hepática e renal por levantamento de prontuário e comparados os grupos. RESULTADOS: 15% (6/40) dos pacientes apresentaram VRT ≥ 2,5m/s, sugestivo de HP, sendo que destes pacientes todos tinham diagnóstico de Anemia Falciforme (AF). Considerando apenas esta população, a prevalência de HP aumenta para 20% (6/30). A população com VRT ≥ 2,5m/s apresentou média de idade mais elevada, Hb mais baixa, RDW mais alargado, reticulócitos e LDH mais elevado que o grupo com VRT < 2,5m/s. A principal intercorrência clínica nesta população foi a ocorrência de priapismo (p< 0,05). CONCLUSÕES: Os pacientes com Hemoglobinopatias estão em risco aumentado para desenvolvimento de HP desde a infância, principalmente aqueles com AF. Estes pacientes apresentam os parâmetros laboratoriais sugestivos de hemólise alterados, assim como outros sintomas associados ao quadro hemolítico como o priapismo quando comparados com pacientes com VRT normal. Desta forma sugere-se a realização de triagem com ecocardiograma nesta população de forma precoce. / INTRODUCTION: The Hemoglobinopathies can be divided in Thalassemias and Sickle Cell Disease (SCD), but clinically both present with chronic hemolytic anemia, which leads to various complications, one of them being Pulmonary Hypertension (PH). About 20-40% of patients with SCD have PH, and this diagnosis is associated with a high risk of mortality. The objective of this study was to estimate the prevalence of this complication in the pediatric population, and associate clinical and laboratory characteristics. METHODS: A cross sectional descriptive study, with the evaluation of 45 patients with diagnosis of SCD or thalassemia major/intermedia between 3-18 years, which received treatment at the Hemoglobinopathies ambulatory at HCPA. The patients were submitted to an echocardiogram to estimate the pulmonary artery systolic pressure, being considered to have PH patients with a tricuspid regurgitate jet velocity (TRV) ≥ 2.5m/s. Clinical and laboratory data were obtained to evaluate hemolytic parameters, renal and liver function and compared between groups. RESULTS: 15% (6/40) of patients had a TRV ≥ 2.5m/s, suggestive of PH, of which all had Sickle Cell Anemia (SCA). Considering this group of patients alone the prevalence would be of 20% (6/30). Patients with TRV ≥ 2.5m/s had a higher median age, lower hemoglobin count, higher RDW, reticulocyte and DHL then patients with a TRV < 2.5m/s. The major clinical feature was the occurrence of priapism (p<0,05). CONCLUSIONS: Patients with diagnosis of hemoglobinopathies are at higher risk of developing PH since early childhood, especially those with SCA. These patients showed a higher level of hemolytic parameters, as well as symptoms associated with hemolysis, like priapism, when compared with patients with a normal TRV. Therefore, it would be indicated to submit these patients to an echocardiogram routinely in their early years.

La drépanocytose est une maladie chronique et génétique de l’hémoglobine. Elle se caractérise par la survenue très précoce de crises de douleurs extrêmement intenses et le plus souvent imprévisibles. Le seul traitement qui permet, à l’heure actuelle, d’obtenir la guérison du malade est la transplantation de cellules souches hématopoïétiques à partir d’un donneur compatible et apparenté. Or, si la greffe est curative, elle est aussi un processus dangereux et incertain qui conduit à une prise de risque importante. En outre, la guérison n’offre pas le retour à un état de santé d’avant la maladie, mais l’accès à un état inédit et jusque-là inconnu, elle conduit donc le sujet à opérer d’importants remaniements, notamment identitaires.Dans une première partie, nous décrirons la drépanocytose dans ses dimensions somatiques, anthropologiques et psychiques afin de déployer les différents aspects qui contribuent à sa puissance identificatoire. Puis, nous nous intéresserons aux effets de la greffe et aux remaniements qu’elle provoque, depuis son annonce et jusqu’à 20 ans après la transplantation. Notre objectif est d’interroger la notion de guérison telle qu’elle est annoncée par le monde médical et de soutenir qu’elle ne peut se réduire aux seuls effets somatiques. Nous souhaitons, ainsi, plaider pour l’organisation systématique d’un accompagnement des effets psychiques induits par ce processus complexe, radical et profondément bouleversant, à toutes ses étapes, tant chez l’adulte que chez l’enfant. / Sickle cell disease is a chronic and genetic disease of hemoglobin. It is characterized by the very early onset of extremely intense and often unpredictable pain attacks. The only treatment that currently enables the patient to be cured is the transplantation of hematopoietic stem cells from a compatible and related donor. However, if the graft is curative, it is also a dangerous and uncertain process that leads to significant risk taking. In addition, healing does not offer a return to a state of health before the disease, but access to a new and unknown state, it leads the subject to make major changes, notably identitary.In a first part, we will describe sickle cell disease in its somatic, anthropological and psychic dimensions in order to deploy the various aspects that contribute to its identificatory power. Then, we will focus on the effects of the transplant and the changes it causes, since its announcement and until 20 years after transplantation. Our goal is to question the notion of healing as it is announced by the medical world and to argue that it can not be reduced only to somatic effects. We thus wish to advocate for the systematic organization of an accompaniment of the psychic effects induced by this complex radical and deeply upsetting process, at all its stages, for the adult as well as for the child.

Intracellular polymerization of deoxygenated sickle hemoglobin (Hb S) remains the principal cause of the pathophysiology associated with sickle cell disease (SCD). Naturally occurring and synthetic allosteric effectors of hemoglobin (AEH) have been investigated as potential therapeutic agents for the treatment of SCD. Several aromatic aldehydes, including vanillin, have been studied previously as AEHs for their antisickling activities. Specifically, these compounds form Schiff- base adduct with Hb to stabilize the oxygenated (R) state, increase Hb affinity for O2 and concomitantly prevent the hypoxia-induced primary pathophysiology of Hb S polymerization and RBC sickling, in turn, ameliorating several of the cascading secondary adverse effects. These compounds, however, undergo significant metabolism leading to suboptimal pharmacokinetic properties, e.g. short duration of pharmacologic action and low bioavailability. These drawbacks have severely hampered the use of aromatic aldehydes as AEHs to treat SCD. To counter these challenges, we designed and synthesized 14 novel compounds (PP- compounds) based on previously studied pyridyl derivative of vanillin. These modifications were expected to increase binding interactions with the protein and thus stabilize the Schiff-base adduct, as well as lead to perturbation of the surface-located F-helix that would stereospecifically destabilize polymer contacts. We investigated the in vitro pharmacokinetic/pharmacodynamic properties of these newly synthesized compounds to ascertain sustained binding and modification of normal human Hb. Subsequently, we conducted in vitro screening assays to test for inhibition of sickling, modification of Hb to the high-affinity form, as well as for a direct left-shift in oxygen equilibrium curves (OEC). Three selected compounds, PP6, PP10, and PP14, that demonstrated not only high antisickling activity but also showed sustained pharmacologic action were chosen for preliminary in vivo studies. Our results showed maximal levels of Hb modification, which were sustained for the entire 24 h experimental period. In contrast, TD-7 after reaching maximum effect at 1 h gradually decreased in potency and at 24 h has lost 45% of its activity, consistent with the low bioavailability of this compound. These findings suggested that our modifications appeared to successfully limit drug metabolism in red blood cells. Most of these compounds showed almost complete inhibition of sickling at 2 mM concentration; with significant modification of Hb to a higher affinity Hb as well as an increase in O2 affinity of Hb. Interestingly, while TD-7 demonstrated a clear linear correlation between its ability to increase Hb-O2 affinity and antisickling activity, PP2, PP3, PP6, PP9, PP10, and PP14, showed a weak correlation between these parameters. In fact, these compounds demonstrated high antisickling effect despite only marginally increasing Hb affinity for O2. This observation indicated that these compounds possibly exhibit the dual mechanism of antisickling activity. We hypothesize that their secondary mechanism of action is due to interactions with the surface located αF-helix that would lead to direct or stereospecific inhibition of polymer formation. To establish the mode of interaction with Hb, we further conducted x-ray crystallography studies and co-crystallized PP2, PP6, PP9 and PP11 with CO-liganded Hb. Our studies showed that these compounds bind in symmetry-related fashion at the α-cleft of Hb to form Schiff-base adducts with the N-terminal Val1 and showed direct interactions with the F-helix which overall enhanced interactions with Hb. PP6, PP10, and PP14 demonstrated significant in vivo modification of intracellular Hb in mice after IP administration, with increasing levels from 1 h to the 6 h experimental period. They also showed corresponding changes in O2 affinity observed at 3 h and 6 h, compared to 0 h pre-treatment samples in vivo. Thus, our results establish these compounds as a novel, promising group of potent anti-sickling agents, demonstrate their proposed mechanism of action and provide proof-of-concept justifications for our structure-based approach to developing potent therapeutics for SCD.

Because of the high mortality rate of sickle cell disease (SCD) patients who do not continue care into adulthood, researchers have paid increasing attention to the health care transition experiences of SCD patients. However, a gap exists regarding patients' perspectives of care transition related to their quality of life. The purpose of this phenomenological study, guided by the biosocial-ecological systems model, was to explore the lived health care transition experiences of SCD patients in relation to their health-related quality of life. Data collection included open-ended interviews with 12 patients in the Southwestern United States. Colaizzi's (1978) method of phenomenological data analysis was used to identify themes, including resistance to transition; inadequate transitional support; lack of autonomy and education; fear, anxiety, and stress; and managing other life changes. Results contribute to the existing research on SCD health care transition, broaden understanding of the transition process and provide guidance for improving transition programs.

Children with Sickle Cell Disease (SCD) face medical, psychosocial, and cognitive challenges, which may impede their social and academic functioning. These complications can be lessened through the implementation of comprehensive interventions. This study reviews one comprehensive intervention, a support group, for children with SCD and their families, and reviews the challenges faced by the children and family who participate in the support group as well as those who do not participate. The study has a mixed-method design because the families participated in focus groups, and they completed quantitative instruments, including a knowledge survey, a behavior rating scale, and an instrument to measure the degree that SCD affects one's life. Most children rated SCD as affecting their life a little bit and were knowledgeable in SCD. The children who did not participate in the support group reported less symptoms and a smaller impact on their lives than those who did participate. The results from the behavior rating scale did not reveal any significant behavior problems in these children; however, those who did not participate in the support group had higher ratings than those who did. These results imply that individuals with SCD who are less impacted by the disease may be less likely to attend a support group than those who are more impacted. Additionally, a theme analysis from the focus groups revealed key themes, such as keeping SCD a secret, getting made fun of, missing school, missing PE class, hospital visits, and experiences with pain crises. The findings from this study indicate that SCD does impact the life of children with the disease; however, the impact may be unknown to others and may differ among individuals. The results also imply that school personnel and other students in schools must be accurately informed about the manifestations of SCD to best promote healthy physical and psychosocial development in children with SCD. Finally, support groups can help to reduce symptoms and complications related to the disease.

Until first half of the XX century, sickle cell disease was practically limited to the malaria endemic areas and countries having known an important surge of African slaves. Today, migratory flows and progress of medicine have modified considerably the distribution of sickle cell disease which is from now on a frequent affection in Western Europe. The preventive implementation of medical care makes it possible to reduce morbidity and mortality associated with this pathology. Stake of a medical policy and economic interests, neonatal screening for hemoglobin disorders justifies then fully the implementation of powerful and adapted means. In order to initiate a newborn screening programme in our centre, we developed various immunological tests allowing to identify the sickle hemoglobin. We first of all developed an indirect immunoassay and led a population study on 46082 Belgian newborns and 1825 neonates from Central Africa. The performances of this assay were improved thereafter by conceiving a competitive test. Next, for reasons independent of our will, we had unfortunately to abandon the immunological approach. This methodology was thus supplanted in our center by an innovative method for this indication: the mass spectrometry. Our promising results currently authorize us to perennialize our policy in the neonatal screening for sickle cell disease and open the way for new developments in other fields. / Jusquà la première moitié du XXe siècle, la drépanocytose se limitait pratiquement aux zones dendémie palustre et aux pays ayant connu un important afflux desclaves dorigine africaine. Aujourdhui, les flux migratoires et les progrès de la médecine ont considérablement modifié la distribution de cette maladie qui est désormais une affection fréquente en Europe occidentale. La prise en charge précoce permet de réduire la morbidité et la mortalité associées à cette maladie. Enjeu dune politique sanitaire et dintérêts économiques, le dépistage néonatal de la drépanocytose justifie donc ainsi pleinement la mise en uvre de moyens performants et adaptés. Afin dinitier un programme de dépistage au sein de notre centre, nous avons initialement développé divers tests immunologiques permettant didentifier lhémoglobine anormale. Nous avons tout dabord mis au point un immunoessai indirect et conduit une étude de population sur 46082 nouveau-nés belges et 1825 bébés originaires dAfrique centrale. Les performances de lessai ont par la suite été améliorées en concevant un test compétitif. Lapprovisionnement laborieux danticorps nécessaires aux tests de détection a par la suite entravé notre programme. En effet, la commercialisation en a été interrompue et la production danticorps monoclonaux par nos moyens propres na pas été couronnée du succès escompté. Lapproche immunologique du dépistage néonatal de la drépanocytose a ainsi été supplantée dans notre centre par une méthode novatrice pour cette indication : la spectrométrie de masse. Nos résultats prometteurs nous autorisent actuellement à pérenniser notre nouvelle façon de faire dans le dépistage néonatal de la drépanocytose et ouvre la voie pour de nouveaux développements dans dautres domaines.

Pregnancy in women with hemoglobinopathy has been associated with an increased risk of adverse pregnancy outcomes. We conducted a historical cohort study using Discharge Abstract Database for the fiscal year 1991-1992 through 2007-2008. We estimated the frequency of pregnant women with hemoglobinopathy and examined their associations with adverse pregnancy outcomes. Women with sickle cell disease are more likely to develop pre-eclampsia and preterm labor, and to undergo cesarean delivery than women with nutritional deficiency anemia, suggesting that there are other mechanisms beyond anemia that may be responsible for an increased risk of adverse pregnancy outcomes. The data suggested a synergistic effect of hemoglobinopathy and pre-eclampsia on preterm labor and cesarean delivery. Prediction models for pre-eclampsia, preterm labor and cesarean delivery were created and internally validated for women with hemoglobinopathy, with satisfactory discrimination and calibration.

This thesis investigated the role of CBF assessment in the management of stroke in children with sickle cell disease (SCD). It is divided into two parts. In the first part, a systematic review of CBF assessment using different imaging modalities in SCD children was designed. The prevalence of CBF abnormalities was found to be equal to or higher than those of structural MRI and transcranial Doppler (TCD) in SCD children who have not experienced stroke. Studies reviewed suggested CBF assessment in SCD could aid in addressing brain abnormalities at the tissue level. In the second part, the arterial spin labeling (ASL) technique was used to depict CBF abnormalities in SCD children. ASL demonstrated perfusion abnormalities that seem to remain invisible in TCD measurements; CBF interhemispheric asymmetries were associated with clinically silent infarctions with no corresponding flow velocity interhemispheric asymmetries assessed with TCD.

This thesis investigated the role of CBF assessment in the management of stroke in children with sickle cell disease (SCD). It is divided into two parts. In the first part, a systematic review of CBF assessment using different imaging modalities in SCD children was designed. The prevalence of CBF abnormalities was found to be equal to or higher than those of structural MRI and transcranial Doppler (TCD) in SCD children who have not experienced stroke. Studies reviewed suggested CBF assessment in SCD could aid in addressing brain abnormalities at the tissue level. In the second part, the arterial spin labeling (ASL) technique was used to depict CBF abnormalities in SCD children. ASL demonstrated perfusion abnormalities that seem to remain invisible in TCD measurements; CBF interhemispheric asymmetries were associated with clinically silent infarctions with no corresponding flow velocity interhemispheric asymmetries assessed with TCD.

Pregnancy in women with hemoglobinopathy has been associated with an increased risk of adverse pregnancy outcomes. We conducted a historical cohort study using Discharge Abstract Database for the fiscal year 1991-1992 through 2007-2008. We estimated the frequency of pregnant women with hemoglobinopathy and examined their associations with adverse pregnancy outcomes. Women with sickle cell disease are more likely to develop pre-eclampsia and preterm labor, and to undergo cesarean delivery than women with nutritional deficiency anemia, suggesting that there are other mechanisms beyond anemia that may be responsible for an increased risk of adverse pregnancy outcomes. The data suggested a synergistic effect of hemoglobinopathy and pre-eclampsia on preterm labor and cesarean delivery. Prediction models for pre-eclampsia, preterm labor and cesarean delivery were created and internally validated for women with hemoglobinopathy, with satisfactory discrimination and calibration.