Orientador: Fábio Hüsemann Menezes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-16T07:54:40Z (GMT). No. of bitstreams: 1 Medeiros_CharlesAngottiFurtadode_D.pdf: 4155361 bytes, checksum: a61d12a8785ffe83230f77cc5e0b8fde (MD5) Previous issue date: 2010 / Resumo: Objetivo: Medir o volume de fluxo arterial com mapeamento duplex, calcular a relação do volume de fluxo fêmoro/axilar e discutir a sua utilidade como um novo índice no significado hemodinâmico de uma lesão obstrutiva no segmento aorto-ilíaco. Metodologia: Diversas medidas de volume de fluxo foram obtidas consecutivamente com mapeamento duplex em artérias femorais comuns e axilares de voluntários sadios sem sinais de aterosclerose e de pacientes com diagnóstico comprovado de doença obstrutiva no segmento aorto-ilíaco por meio da medida de pressão segmentar. Posteriormente, o grupo dos pacientes foi submetido à avaliação complementar com segundo exame confirmatório. Resultados: No total, foram executadas 635 medidas de volume de fluxo em dez voluntários sadios e em oito pacientes com estenose severa ou oclusão de artéria ilíaca, sendo dois destes com doença bilateral. Quando se comparou os sujeitos normais e os pacientes com estenose severa ou oclusão de artéria ilíaca houve diferença significativa estatística entre estes dois grupos (p < 0.01 Mann-Whitney). Resultado semelhante foi encontrado na comparação dos membros doentes dos pacientes com seus próprios membros contralaterais normais (p < 0.05 Wilcoxon). A medida do volume de fluxo somente durante a fase sistólica mostrou ser um parâmetro muito mais sensível para diferenciar membros normais de membros alterados. Além disso, ficou demonstrado boa relação entre o índice de pressão de coxa proximal e o índice de fluxo sistólico fêmoro/axilar no grupo dos pacientes com estenose severa ou oclusão de artéria ilíaca (p < 0.01 Correlação de Spearman). Conclusão: O índice que relaciona o volume de fluxo arterial fêmoro/axilar é confiável na avaliação do significado hemodinâmico da doença obstrutiva no segmento aorto-ilíaca e, poderá ser utilizado como uma ferramenta útil durante o segmento destes doentes / Abstract: Objective: To measure the arterial volume flow with duplex scan, calculate femoral/axillary volume flow ratio and discuss its applicability as a new index for the hemodynamic significance of an aorto-iliac occlusive lesion. Methods: Several measures of volume flow were obtained consecutively with duplex scan in both common femoral and axillary arteries of healthy volunteers with no signs of atherosclerosis and patients with documented evidence of occlusive aorto-iliac disease with segmental pressure measurement. Then patients group was sent to complimentary evaluation with a second confirmatory exam. Results: There were a total of 635 measures of volume flow performed in ten healthy volunteers and eight patients with iliac severe stenoses or occlusion, two of then with bilateral disease. When comparing normal subjects and patients with iliac severe stenoses or occlusion there was statistical significant difference between these two groups (p < 0.01 Mann-Whitney). Similar result was found when comparing patient diseased limbs with their own contra-lateral normal side (p < 0.05 Wilcoxon). And measuring the volume flow only during the systolic phase was a much more sensitive parameter for differentiate normal from diseased. Besides that there was found a good correlation between proximal thigh pressure index and femoral/axillary systolic flow ratio in the patients group (p < 0.01 Spearman Correlation). Conclusion: The femoral/axillary volume flow ratio is useful in assessing the hemodynamic significance of aorto-iliac disease and systolic femoral/axillary ratio may also be useful as a follow-up tool / Doutorado / Doutor em Cirurgia

O tromboembolismo pulmonar causado por obstrução de ramos arteriais pulmonares por trombos originados de outras partes do corpo apresenta elevada incidência. Em 5% dos casos ocorre a cronificação do processo e manutenção ou agravamento da hipertensão pulmonar Duas hipóteses explicam a cronificação nos casos de embolia pulmonar: 1. manutenção do fator oclusivo como fundamental para o desenvolvimento da resposta vascular pulmonar caracterizada por hipertrofia da camada média; 2. hipertensão pulmonar secundária a uma arteriopatia inicial, nos pacientes que evoluíram de maneira desfavorável. Este estudo tem por objetivo avaliar sob critérios histopatológicos qualitativos e quantitativos o comportamento do leito arterial pulmonar distal (pré e intra-acinar), comparativamente em pulmões de pacientes sem tromboembolismo prévio e de pacientes portadores de tromboembolismo agudo e crônico. Para tanto, estudou-se a resposta vascular através de estudo histológico de 31 casos de embolia (aguda e crônica), comparando-os com 24 pacientes do grupo controle (Infarto agudo do miocárdio) (análise de autópsias). As lâminas de tecido pulmonar foram preparadas e coradas em hematoxilina-eosina e Miller. A análise realizada foi dividida em qualitativa (vasoconstrição e proliferação intimal concêntrica) e quantitativa (hipertrofia da camada média). Foram observadas alterações histopatológicas do leito arterial pulmonar distal nos pacientes portadores de quadro tromboembólico agudo e crônico, em relação aos pacientes sem tromboembolismo prévio. Estas alterações, entre os grupos agudo e crônico, foram: diferentes quanto aos critérios qualitativos, caracterizadas por maior vasoconstrição nos quadros tromboembólicos agudos e maior proliferação intimal concêntrica nos crônicos; semelhantes quanto aos critérios quantitativos, caracterizadas por hipertrofia da camada média. A isquemia decorrente da obstrução parece exercer um importante papel nestas alterações, o que, entretanto, necessita de comprovação futura / The pulmonary embolism, caused by pulmonary artery branches obstruction from thrombus originated on other parts of the body, has a high incidence. However, just 5% of the cases develop the cronification and pulmonary hypertension. Two hypotheses can explain the cronification of tromboembolic pulmonary events: 1. maintenance of occlusive factor with pulmonary vascular response characterized by medial hypertrophy; 2. pulmonary hypertensive response as an initial arteriopathy in patients with bad evolution. This study aims to evaluate histologic aspects of pulmonary arterial bed (quantitative and qualitative), and to compare the results from embolic cases with non embolic cases. The study evaluated 55 patients (31 with pulmonary embolic disease and 24 in the control group myocardium infarction). From the selected cases, the blades with pulmonary tissue were colored by two techniques (haematoxilin-eosin and Miller). The analysis encompassed qualitative (vasoconstriction and intimal proliferation) and quantitative (mensuration of medial thickness) observations. It has been observed histologic changes between the two groups with pulmonary embolic disease (chronic or acute), and the control group. The changes between the embolic groups were: 1. higher vasoconstriction in the acute group, 2. more intimal proliferation in the chronic group, 3. no difference in the quantitative response (medial thickness). The ischemic response to obstruction can perform an important role in these changes, but further studies are necessary. There was a similar response in chronic and acute cases

Orientador: Joyce Maria Annichino-Bizzacchi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T17:15:50Z (GMT). No. of bitstreams: 1 Paula_ErichViniciusde_D.pdf: 3311580 bytes, checksum: 0e2725586b5aed078f6a78de1edd1d14 (MD5) Previous issue date: 2006 / Resumo: A doença arterial oclusiva (DAO) é a principal causa de morbidade e mortalidade em países industrializados. Com o aumento da expectativa de vida da população mundial a DAO tornou-se um problema de saúde publica também em países em desenvolvimento. O tratamento de uma das formas graves de DAO, a isquemia crítica de membros inferiores (ICMI), normalmente oferece alívio temporário e muitas vezes requer a amputação do membro afetado. No Brasil, a sobrevida desses pacientes é comparável a algumas formas de câncer. Desta forma, a busca de estratégias terapêuticas alternativas à amputação é fundamental para estes pacientes. Nesse estudo, nós exploramos o papel da angiogênese terapêutica induzida por terapia gênica (TG) em modelos animais ICMI. A angiogênese terapêutica se baseia na utilização de fatores de crescimento vascular sob a forma de proteínas recombinantes ou TG. A reposição de proteína deve ser mantida por períodos prolongados e normalmente requer administração sistêmica. Isto aumenta o risco de formação de vasos em locais indesejáveis como tumores ocultos ou retina. Estudos clínicos anteriores demonstraram que a indução de angiogênese terapêutica utilizando apenas um fator pró-angiogênico é eficaz. No entanto, esses estudos sugerem que integridade destes neovasos é deficiente pela ocorrência de edema de membros inferiores ou proteinúria após a monoterapia angiogênica.Neste trabalho avaliamos a eficácia da TG combinada usando vetores não virais com os genes de dois fatores de crescimento: FGF-2 e PDGF-BB, em comparação com a transferência gênica isolada do VEGF-A. A escolha destes dois fatores deveu-se ao fato de eles atuarem em etapas distintas e complementares do processo de formação vascular: formação e estabilização dos novos vasos, respectivamente. Para este fim utilizamos o modelo de isquemia da pata posterior em ratos, e um novo método não invasivo, o 99mTc-sestamibi para avaliação da neovascularização. A expressão combinada do FGF-2 e PDGF-BB induziu a formação de neovasos com a mesma intensidade e com a mesma relevância funcional que o uso do VEGF-A isolado. No entanto, a estratégia combinada se mostrou mais atraente por induzir a formação de vasos mais íntegros, e necessitar de doses individuais 50% menores de cada gene terapêutico. Em conjunto esses dados demonstram que a TG combinada com FGF-2/PDGF-BB é eficaz e potencialmente mais segura para o tratamento da ICMI. Com o objetivo de definir fatores que afetam a resposta angiogênica pós-natal, nós investigamos o papel da trombina durante a indução de neovasos. Animais receberam diversos inibidores da coagulação imediatamente ou após 72 horas da indução de isquemia periférica. Nós documentamos que a inibição da coagulação sangüínea na fase aguda da isquemia diminui a resposta angiogênica, mas esse efeito não é observado quando a anticoagulação é iniciada após 72 horas. A ativação dos receptores celulares da trombina (e outras proteases) pode oferecer um novo alvo para otimizar a resposta angiogênica pós- natal. Em conjunto, os resultados obtidos formam a base para estudos futuros utilizando a TG combinada com FGF-2/PDGF-BB como uma alternativa potencialmente eficaz e segura paro tratamento da ICMI / Abstract: Arterial occlusive disease (AOD) is the main cause of mortality and morbidity in industrialized countries. Global improvements in life expectancy have turned it into a public health problem in developing countries as well. The treatment of one of the severe presentations of DAO, which is critical limb ischemia (CLI) normally offers temporary relief to symptoms, often requiring major amputations of the affected limb. In Brazil, the prognosis of CLI is similar to that of some forms of cancer. Therefore, new therapeutic strategies alternative to amputations are necessary for these patients. In the present work we evaluated the role of therapeutic angiogenesis induced by gene therapy (GT) in animal models of CLI. Therapeutic angiogenesis consists in the use of vascular growth factors by means of recombinant proteins or GT. When using protein formulations, therapy must be maintained for prolonged periods and normally involves systemic administration. These requirements increase the risk of inducing the formation of neovessels in undesired places such as occult malignant lesions or retina. Previous studies have demonstrated that therapeutic angiogenesis using a single pro-angiogenic factor is effective. However, these studies suggest that the new formed vessels are leaky, as evidenced by the occurrence of lower limb edema and proteinuria after pro-angiogenic monotherapy. In the present work we evaluated efficacy of a combined GT strategy using non-viral vectors expressing two vascular growth factors: FGF-2 and PDGF-BB, and compared this strategy to the gene transfer of VEGF-A alone. The choice of these two growth factors was due to their complementary roles in the process of vascular development: formation and stabilization of new vessels. In order to do so we used a hindlimb ischemia model in rats, and a new non-invasive method based on 99mTc-sestabimi scintigrapy, to evaluate the neovascularization response. Dual gene transfer of FGF-2 and PDGF-BB using non-viral vectors was able to induce a similar revascularization response as VEGF-A alone, both in terms of anatomical and functional parameters. In regard to safety, the dual gene transfer strategy was more attractive because it was able to induce more stable capillaries, and required a 50% lower individual dose of each therapeutic gene. Taken together our data demonstrate that this dual gene transfer strategy is an effective safer strategy for the treatment of CLI by therapeutic angiogenesis. In order to investigate factors that might affect the revascularization post-natal response, we further investigated the role of thrombin during the induction of neovascularization. Animals were treated with different coagulation inhibitors immediately after or 72 hours after the creatin of hindlimb ischemia in rats. We documented that the inhibition of blood coagulation in the acute phase of ischemia impairs the angiogenic response. In contrast, this effect was not observed when anticoagulation was initiated after 72 hours of ischemia. The activation of cellular receptors of thrombin and other proteases might therefore offer an new target to optimize post-natal revascularization. Based on our results, future studies using combined GT with FGF-2 and PDGF-BB are warranted in order to translate these findings into a new and safer strategy for the treatment of CLI / Doutorado / Medicina Experimental / Doutor em Fisiopatologia

Peripheral arterial occlusive disease (PAOD) is a globally-prevalent cardiovascular disease in which atherosclerotic plaques narrow arterial lumen diameters and restrict blood flow to downstream tissues. The impact of these occlusions can be mitigated by collateral vessels that connect parallel arterial branches and act as natural bypasses to maintain perfusion. In animal models that lack collateral arterioles, capillaries that connect terminal arteriolar segments can arterialize and form functional collaterals following an ischemic event; however, in the early stages of development, vasodilation is impaired. We explored the mechanism of impaired vasodilation in arterialized collateral capillaries (ACCs) and pre-existing collaterals (PECs) by evaluating endothelial-dependent vasodilation and endothelial-independent reactivity at day seven following the ischemic event. We also evaluated functional vasodilation in mature ACCs and PECs at day 21 by applying vasodilation inhibitors during the electrical stimulation of muscle contraction. Arterial occlusion was performed by ligating the cranial-lateral spinotrapezius feed artery in Balb/C mice, a strain that either lacks native arteriolar collaterals or contains a single collateral arteriole (~50% of mice), as opposed to the C57Bl/6 strain, which each contain 10 or more collateral arterioles. At seven days post-surgery, both vasodilation and vasoconstriction were impaired in ACCs when compared to terminal arterioles of similar size in unoperated limbs, but still exhibited significant changes when compared to baseline. The comparable reactivity in both endothelial-dependent and independent vasodilation at day-seven in ACCs indicates that vascular smooth muscle cells are likely responsible for the impairment, as they may still be developing, rearranging, or both, and are not yet fully capable of regulating diameter in immature ACCs. However, by 21 days post-ligation, ACCs regained the capacity to dilate in response to muscle contraction, and utilized similar vasodilation pathways as control vessels. At seven days post-ligation, PECs had impaired endothelialindependent dilation, but successful endothelial-dependent dilation, indicating the use of alternative pathways to dilate. Unlike ACCs, the PECs never completely restored vasodilation capabilities by day 21, which may be due to a variation in smooth muscle phenotype, sensitivity to vasoactive agents, and/or limited growth factor expression. For future work, evaluating collateral formation and vasodilation in a diseased model and investigating molecular variations in the smooth muscle may yield additional knowledge that can improve therapies for patients during ischemic events.

Since the 1900s, the number of deaths attributable to cardiovascular disease has steadily risen. With the advent of antihypertensive drugs and non-invasive surgical procedures, such as intravascular stenting, these numbers have begun to level off. Despite this trend, the number of patients diagnosed with some form of cardiovascular disease has only increased. By 2030, prevalence of coronary heart disease is expected to increase approximately by 18% in the United States. By 2050, prevalence of peripheral arterial occlusive disease is expected to increase approximately by 98% in the U.S. No single drug or surgical intervention offers a complete solution to these problems. Thus, a multi-faceted regimen of lifestyle changes, medication, and device or surgical interventions is usually necessary. A potential adjunct therapy and cost-effective solution for treating cardiovascular disease that has been overlooked is neurostimulation. Recent studies show that using neurostimulation techniques, such as transcutaneous electrical nerve stimulation (TENS), can help to reduce ischemic pain, lower blood pressure, increase blood flow to the periphery, and decrease systemic vascular resistance. The mechanisms by which these hemodynamic changes occur is still under investigation. The primary aim of this thesis is to elucidate these mechanisms through a thorough synthesis of the existing literature on this subject. Neurostimulation, specifically TENS, is thought to modulate both the metaboreflex and norepinephrine release from sympathetic nerve terminals. To test the hypothesis that TENS increases local blood flow, decreases mean arterial pressure, and decreases cutaneous vascular resistance compared to placebo, in which the electrodes are attached but no electrical stimulation is applied, a protocol was developed to test the effect of neurostimulation on healthy subjects. Implementation of this protocol in a pilot study will determine if neurostimulation causes significant changes in blood flow using the most relevant perfusion measurement instrumentation. Before conducting this study, pre-pilot comparison studies of interferential current therapy (IFC) versus TENS, low frequency (4 Hz) TENS versus high frequency (100 Hz) TENS, and electrode placement on the back versus the forearm were conducted. The only statistically significant difference found was that the application of IFC on the back decreased the reperfusion time, meaning that the time required to reach the average baseline perfusion unit value after occlusion decreased. Further pre-pilot work investigating these different modalities and parameters is necessary to ensure that favorable hemodynamic changes can be detected in the pilot study.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21671号 / 医博第4477号 / 新制||医||1035(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 溝脇 尚志, 教授 黒田 知宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Peripheral arterial occlusive disease (PAOD) affects 8 to 12 million Americans over the age of 50. As the disease progresses, arterial occlusions arising from atherosclerotic lesions inhibit normal metabolic vasodilation in the peripheries, resulting in limb ischemia and claudication. Pharmacological and surgical treatments currently used to treat both the hemodynamic and pain symptoms associated with PAOD can involve adverse and potentially life-threatening side effects. Thus, there is a need for additional innovative therapies for PAOD. Neurostimulation has a known analgesic effect on both acute and chronic pain. Although the exact mechanisms remain under investigation, local vascular tone may be modulated by neurostimulation in addition to pain modulation. The Gate Control Theory proposes that electrical activation of mechanoreceptive afferent somatosensory nerves, specifically Aβ fibers, inhibits pain signaling to the brain by activating an inhibitory interneuron in the dorsal horn of the spinal cord which dampens signaling from afferent, C type peripheral nociceptor nerves. Interestingly, Aβ fiber activation may also inhibit norepinephrine release from sympathetic nerve terminals on efferent neurons by activating α-2 adrenergic receptors along the same dermatome, resulting in localized vasodilation in both limbs. Ultimately, electrical stimulation may decrease mean blood pressure and increase local blood flow. The focus of this study was to optimize protocols and perform a small scale clinical study to investigate hemodynamic and analgesic responses to neurostimulation during acute ischemia. We hypothesized that ganglial transcutaneous electrical neurostimulation (TENS) and interferential current (IFC) treatments would decrease pain perception and vascular resistance in the periphery in young, healthy subjects. We further hypothesized that IFC may have a greater hyperemic and analgesic effect on acute ischemia than TENS as its current waveform may be more efficient at overcoming skin impedance. Interestingly, we found trends suggesting that TENS and IFC may increase vascular resistance (VR) and have no noticeable analgesic effect, though TENS may have a slightly lower increase in VR associated with an increase in pain. Further work characterizing the hemodynamic effects of different stimulus waveforms is needed to inform future research into possible neuromodulation therapies for ischemic disease.

A partir du défaut premier de la drépanocytose, la polymérisation de l’hémoglobine S (HbS), se développe toute une série de processus anormaux qui contribuent au développement d’une réponse inflammatoire et d’un stress oxydant dus à une hypoxie-reperfusion traumatisante et à l’auto-oxydation de l’HbS. L’exacerbation du stress oxydatif semble participer de manière active aux mécanismes physiopathologiques de la maladie et jouer un rôle dans la survenue des crises vaso-occlusives (CVO). Les travaux menés dans le cadre de cette thèse avaient pour objectif de mieux documenter les effets délétères du stress oxydant sur le globule rouge et son impact dans le développement des CVO. Nous avons, en premier lieu, évalué in vitro l’impact du stress oxydant sur la rhéologie sanguine des patients drépanocytaires SS et SC à l’aide d’un agent à fort potentiel oxydant, le t-butyl hydroperoxide (TBHP). Nous avons montré que les globules rouges des patients drépanocytaires (GR SS) produisent en présence du TBHP davantage de radicaux libres que les GR provenant de sujets contrôles (GR AA) et que ces GR SS présentent un système de défense anti-oxydant diminué. L’induction d’un stress oxydant accentue les altérations rhéologiques déjà présentes chez les patients drépanocytaires (i.e, déformabilité diminuée, diminution de l’indice d’agrégation, augmentation du seuil de désagrégation) tandis qu’il induit chez les sujets contrôles un profil hémorhéologique altéré proche de celui déjà préexistant chez les patients drépanocytaires. Ces résultats suggèrent que le stress oxydant, en participant aux anomalies hémorhéologiques associées à la drépanocytose, pourrait être l’un des facteurs favorisant la survenue des complications drépanocytaires. Nous nous sommes de plus attachés à documenter directement l’impact du stress oxydant dans le développement des CVO en analysant des prélèvements sanguins provenant de patients drépanocytaires SS en crise et à l’état de base. Il s’agissait : 1) de tester l’hypothèse selon laquelle la protéine bande 3, protéine de la membrane du GR, est une cible majeure des espèces réactives de l’oxygène qui provoquent au niveau de cette protéine l’apparition d’épitopes de senescence reconnus par des auto anticorps anti-bande 3 ; 2) d’évaluer l’évolution de marqueurs moléculaires et cellulaires pro- et anti-oxydants ; 3) d’étudier l’évolution des paramètres hémorhéologiques ; 4) d’explorer l’activité du système nerveux autonome, considéré comme un marqueur potentiel de sévérité. Nous avons mis en évidence au cours des CVO : 1) une exacerbation du stress oxydant ; 2) une diminution du taux d’anticorps anti-bande 3 et une augmentation de la concentration plasmatique de microparticules érythrocytaires, suggérant que ces deux processus sont liés au phénomène de clusterisation de la protéine bande 3 déclenché par le stress oxydant ; 3) une exacerbation des anomalies hémorhéologiques se traduisant par une réduction de la déformabilité érythrocytaire, une augmentation de l’agrégation érythrocytaire et du seuil de désagrégation ; 4) une altération du système nerveux autonome marqué par un retrait de l’activité parasympathique, ce déséquilibre étant accentué au cours des CVO. Les travaux de cette thèse se traduisent par à une meilleure compréhension de la physiopathologie extrêmement complexe de la drépanocytose en précisant l’impact du stress oxydant dans le déclenchement des CVO, première cause d’hospitalisation des sujets drépanocytaires. Les données obtenues, qui mettent en évidence des marqueurs pertinents de ce stress oxydant au cours de la CVO du sujet drépanocytaire, pourront favoriser la mise en œuvre de nouvelles pistes thérapeutiques anti-oxydantes et une amélioration in fine de la prise en charge des patients. / Besides the primary defect of sickle cell disease, hemoglobin S (HbS) polymerization, other abnormal processes may contribute to the development of an inflammatory response and to an oxidative stress caused by traumatic hypoxia-reperfusion and autoxidation of HbS. The exacerbation of oxidative stress seems to participate actively in the pathophysiology of the disease and play a role in vaso-occlusive crisis (VOC). The aim of this thesis was to document the deleterious effects of oxidative stress on the red blood cell and its impact in the development of VOC. First, we have evaluated the impact of tert-butyl hydroperoxide-induced oxidative stress on blood rheology of SS and SC sickle cell patients. We have shown that sickle red blood cells (SS RBC) produce more free radicals in the presence of tert-butyl hydroperoxide (TBHP) than control subject red blood cells (AA RBC). Furthermore, SS RBC have a decreased anti-oxidant defense system. Induction of oxidative stress increases the rheological alterations already present in sickle cell patients (ie, decreased deformability, reduced aggregation, increased disaggregation threshold). In control subjects, oxidative stress induces an altered hemorheological profile close to that already present in sickle cell patients. These results suggest that oxidative stress by modulating the hemorheological abnormalities associated with sickle cell disease, could be one of the factors promoting the occurrence of sickle cell complications. Then, we have studied the impact of oxidative stress in the development of VOC, analyzing blood samples from SS patients in crisis and at steady state. 1) We have tested the hypothesis that the protein band 3 of RBC, is a major target of reactive oxygen species, which cause the appearance of senescence epitopes of this protein recognized by auto anti-band 3 antibodies; 2) We have evaluated pro- and anti-oxidants molecular and cellular markers; 3) We have studied the evolution of hemorheological parameters; 4) We have explored the activity of the autonomic nervous system, seen as a potential marker of severity. Our results show during VOC: 1) an exacerbation of the oxidative stress; 2) a decrease in anti-band 3 antibodies levels and an increase in the plasma concentration of erythrocyte microparticles, suggesting that these two processes are linked to the clustering phenomenon of band 3 protein triggered by oxidative stress; 3) an exacerbation of hemorheological abnormalities resulting in a reduction of SS RBC deformability, increased aggregation and disaggregation threshold; 4) an impairment of the autonomic nervous system marked by a withdrawal of parasympathetic activity and this imbalance is accentuated during VOC. This work allows a better understanding of the complex pathophysiology of sickle cell disease, highlighting the impact of oxidative stress in the development of VOC, the leading cause of hospitalization of sickle cell subjects. The data obtained, which reveal relevant markers of oxidative stress during VOC, could promote the implementation of new antioxidant therapeutic approaches and help improving sickle cell patients care.

O Transplante de Células-Tronco Hematopoéticas (TCTH) é uma terapia complexa que expõe o paciente a inúmeras vulnerabilidades, das quais se destaca a infecção relacionada ao Cateter Venoso Central (CVC). Entre as coberturas oclusivas, o Curativo Impregnado com Gel de Clorexidina (CIGCHX) é uma tecnologia promissora que tem demonstrado eficácia superior na prevenção dessas infecções. Uma característica inovadora é a presença da almofada gel de clorexidina, que mantém ação antimicrobiana, a despeito da presença de matéria orgânica, permitindo permanência de sete dias por propiciar controle do crescimento da microbiota local. Diante disto, propôs-se descrever o uso do CIGCHX como cobertura do CVC inserido em adultos e crianças submetidos ao TCTH e a ocorrência de infecção relacionada ao cateter na vigência deste curativo. Foi conduzido um estudo quantitativo, observacional, descritivo com corte transversal. A casuística compôs-se de 25 pacientes que se submeteram a observações diárias de aspectos relacionados ao CIGCHX até 45 dias após a inserção do primeiro CVC, ou antes, caso este curativo tenha sido suspenso ou o cateter removido, entre setembro de 2013 a fevereiro de 2014. As variáveis foram analisadas por meio de estatística descritiva. O CIGCHX teve permanência média de 4,62 dias, variando entre 0,5 e sete dias. A remoção programada do mesmo ocorreu em 43 dos 104 curativos acompanhados. A presença de sangue foi o principal motivo para remoção não programada do CIGCHX. A presença de bolha de ar sob a almofada gel de clorexidina foi a observação mais frequente sobre o aspecto diário do curativo, presente em 56,7% das avaliações realizadas. O CVC teve permanência média de 14,73 dias, variando entre cinco e 33 dias, com DP 6,78 dias. A infecção relacionada ao cateter foi o principal motivo para sua remoção. Nas culturas de sangue e ponta de cateter, os microrganismos isolados foram todos bactérias gram negativas. Os sinais e sintomas de irritação cutânea na região do CIGCHX ocorreram em cinco pacientes. Os achados relacionados à irritação cutânea podem apontar que o uso do CIGCHX exige cautela na população estudada. A presença de sangue como principal motivo para remoção não programada do curativo revela a especificidade dos pacientes e indica que os fatores relacionados devem ser considerados para o uso do CIGCHX nesta população. O desenvolvimento de estudos experimentais que investiguem as causas e implicações da presença da bolha de ar, bem como dos outros aspectos observados no curativo, é essencial para certificar a eficácia do uso do CIGCHX sob essas condições e propor medidas para manejo, se necessário, para que seja implementado em sua maior potencialidade. Ademais, tais resultados contribuirão para centros de transplante gerenciar o uso do CIGCHX e desenvolver protocolos para sua utilização, com atenção às diversas nuances que seu uso implica. / Hematopoietic Stem-Cell Transplantation (HSCT) is a complex treatment that exposes patients to uncountable vulnerabilities, particularly central venous catheter (CVC) infections. Among the many occlusive dressings, the chlorhexidine-gel-impregnated dressing (CHXGID) is a promising technology that has proven superior effectiveness in preventing CVC infections. One innovative feature of CHXGID is the presence of a chlorhexidine-gel pad that maintains an antimicrobial action despite of the presence of organic material. The dressing can remain on the patient for seven days, thus controlling local microbiota growth. Therefore, it was proposed to describe the use of CHXGID as a dressing of the CVC of adult and child patients undergoing HSTC and the occurrence of catheter-related infections while using that dressing. A quantitative, observational, descriptive and cross-sectional study was conducted. The study sample consisted of 25 patients who agreed to daily observations of aspects related to the CHXGID for 45 days after first CVC insertion, or less in case the dressing or catheter were removed, from September of 2013 to February of 2014. The variables were analyzed using descriptive statistics. The mean CHXGID permanence was 4.62 days, ranging between 0.5 and seven days. Scheduled removal occurred in 39 of the 104 studied dressings. The presence of blood was the main reason for unscheduled CIGCHX removal. The presence of air bubbles under the chlorhexidine-gel pad was the most frequent observation regarding the daily aspect of the dressing, observed in 56.7% of the assessments. The mean CVC permanence was 14.73 days, ranging between five and 33 days, with a SD of 6.78 days. Catheter-related infection was the main reason for its removal. The microorganisms isolated in the blood and catheter tip cultures were all gram negative bacteria. Five patients showed signs and symptoms of skin irritations in the CHXGID area. The findings related to skin irritations suggest that special care is required when using CHXGID in the studied population. The presence of blood as the main reason for unscheduled removing the dressing reveals the specificity of the patients and indicates that the associated factors must be considered for using CHXGID in this specific population. Further experimental studies that investigate the causes and implications of air bubbles, as well as other aspects observed on the dressings, are essential to verify the effectiveness of CHGID under these conditions and to propose any necessary handling measures, so the highest effectiveness of CHGID use can be achieved. Furthermore, such results will help transplant centers manage the utilization of CHXGID and develop specific utilization protocols, with particular care to the diverse levels of implications involved.

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