Indiana University-Purdue University Indianapolis (IUPUI) / HIV-associated cardio-pulmonary vascular pathologies such as coronary artery disease, pulmonary hypertension and emphysema remain a major issue in the HIVinfected population even in the era of antiretroviral therapy (ART). The continued production of HIV encoded pro-apoptotic protein, such as Nef in latently HIV-infected cells is a possible mechanism for vascular dysfunction underlying these diseases. HIVNef persists in two compartments in these patients: (i) extracellular vesicles (EV) of plasma and bronchoalveolar lavage (BAL) fluid and (ii) PBMC and BAL derived cells. Here I demonstrate that the presence of HIV-Nef protein in cells and EV is capable of stressing endothelial cells by inducing ROS production leading to endothelial cell apoptosis. HIV-Nef protein hijacks host cell signaling by interacting with small GTP binding protein Rac1 which activates PAK2 to promote the release of pro-apoptotic cargo containing EV and surface expression of pro-apoptotic protein Endothelial Monocyte Activating Polypeptide II (EMAPII). Using this mechanism, Nef protein robustly induces apoptosis in Human Coronary Artery Endothelial Cells and Human Lung microvascular endothelial cells. Endothelial specific expression of HIV-Nef protein in transgenic mice was sufficient to induce vascular pathologies as evidenced by impaired endothelium mediated vasodilation of the aorta and vascular remodeling and emphysema like alveolar rarefaction in the lung. Furthermore, EV isolated from HIV patients on ART was capable of inducing endothelial apoptosis in a Nef dependent fashion. Of therapeutic interest, EMAPII neutralizing antibodies to block EMAPII mediated apoptosis and statin treatment to ameliorate Nef induced Rac1 signaling was capable of blocking Nef induced endothelial stress in both in vivo and in vitro. In conclusion, HIV-Nef protein uses a Rac1-Pak2 signaling axis to promote its dissemination in EV, which in turn induces endothelial cell stress after its uptake.

O aumento da concentração sérica de testosterona está associado tanto a fatores de risco cardiovascular, incluindo obesidade abdominal e hipertensão arterial, como diretamente a doenças cardiovasculares (DCVs). Há evidências que a testosterona pode modular, positivamente, componentes envolvidos em processos de oxirredução (redox) e inflamatório, incluindo a geração de espécies reativas de oxigênio (EROs) e produção de citocinas próinflamatórias e anti-inflamatórias. O inflamassoma NLRP3 é um componente do sistema imunológico inato e regulador importante da inflamação crônica. Sua ativação pode ser mediada pelo aumento de EROs, contribuindo para o processo inflamatório presente em diversas DCVs. Considerando que a testosterona representa uma fonte importante na produção de EROs, foi testada a hipótese que níveis suprafisiológicos de testosterona induzem ativação do complexo NLRP3 inflamassoma, com consequente prejuízo da função vascular. Esse estudo avaliou se níveis suprafisiológicos de testosterona são capazes de ativar o inflamassoma NLRP3 e se esta ativação contribui para alterações na reatividade vascular. Nosso estudo demonstrou que níveis supra fisiológicos de testosterona alteraram a função vascular, com participação dos receptores para andrógenos em camundongos C57BL/6J wild type (WT). Estes efeitos da testosterona não foram observados em camundongos WT incubados com MCC950 (inibidor do receptor NLRP3) e knockout NLRP3 (NLRP3- / - ). Além disso, a testosterona aumentou a geração vascular de EROs, determinada pela fluorescência de lucigenina e dihidroetidina. A geração de EROs foi prevenida por cianeto de carbonil mclorofenil hidrazona (CCCP), um desacoplador mitocondrial. A testosterona em níveis suprafisiológicos aumentou a expressão vascular de caspase-1 e interleucina-1? (IL-1?), como determinado por Western Blotting e Elisa, respectivamente. Esses dados sugerem que níveis suprafisiológicos de testosterona induzem disfunção vascular via geração de EROs e ativação do inflamassoma NLRP3 / Increased serum testosterone concentration is associated with both cardiovascular risk factors, including abdominal obesity and hypertension, and cardiovascular disease (CVD). There is evidence that testosterone positively modulates components involved in oxidative and inflammatory processes, including the generation of reactive oxygen species (ROS) and production of pro-inflammatory and anti-inflammatory cytokines. NLRP3 inflammasome is a component of the innate immune system and an important modulator of chronic inflammation. NLRP3 activation can be mediated by increased levels of ROS, contributing to chronic inflammation in several CVDs. Considering that testosterone induces ROS production, we tested tested the hypothesis that supraphysiological levels of testosterone activates the NLRP3 inflammasome, with consequent impairment of vascular function. This study evaluated whether supraphysiological levels of testosterone activate NLRP3 inflammasome and whether NLRP3 activation contributes to testosterone-induced vascular dysfunction. Our study demonstrated that supraphysiological levels of testosterone, via activation of androgen receptors, altered vascular function in C57BL/6J wild type (WT) mice. The vascular effects of testosterone were not observed in WT mice incubation with MCC950 (NLRP3 receptor inhibitor) and NLRP3 (NLRP3 - / - ) knockout mice. In addition, testosterone increased vascular generation of ROS, as determined by lucigenin and dihydroetidine the fluorescence. ROS generation was prevented by carbonyl m-chlorophenyl hydrazone cyanide (CCCP), a mitochondrial uncoupler. Testosterone at supraphysiological levels increased the vascular expression of caspase-1 and interleukin-1? (IL-1?), as determined by Western blotting and Elisa, respectively. These data suggest that supraphysiological levels of testosterone induce vascular dysfunction through ROS generation and activation of the NLRP3 inflammasome

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease almost exclusively related to tobacco smoke. COPD symptoms are typical of numerous other ailments making it difficult to diagnose and track. Technological advancements in CT imaging have allowed clinicians and researchers to expand simple structural information to functional information. These advancements have helped to increase the use of CT imaging in the study of smoking related lung disease. In this thesis, we investigate observations from a previous study which suggested pulmonary artery constriction in inflamed lung regions promotes emphysema progression in smokers susceptible to emphysema. We use CT data from a 1 year longitudinal study to evaluate the pulmonary artery dimensions in rapid and non-progressing emphysema subjects. We show that the enlargement of arteries predicts emphysema progression and can be used to identify subjects showing signs of rapid emphysema progression. We attempt to further our ability to use dual energy computed tomography (DECT) for longitudinal and multi-center studies by developing a DECT perfusion blood volume (PBV) imaging protocol with low radiation dose and diluted contrast. We demonstrate that we can reduce radiation dose by up to 34% with the advanced technology of Siemens SOMATOM Force scanner. Finally, we use DECT PBV imaging to compare perfusion heterogeneity in a multi-center study with both GE and Siemens scanners. We show that perfusion heterogeneity is increased in lung regions showing signs of emphysema, but scanner model/manufacturer appears to be the most important factor as data from the GE scanner had greater noise and thus increased perfusion heterogeneity.

Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

No description available.

Os distúrbios na regulação da concentração de cálcio (Ca2+) citoplasmático contribuem para a patogênese da hipertensão arterial. Evidências sugerem que as moléculas de interação estromal (STIM) atuam como sensores dos estoques intracelulares de Ca2+, enquanto as proteínas Orai representam as subunidades que formam os canais de Ca2+ ativados pela liberação de Ca2+ (CRAC). Neste estudo avaliamos a participação de STIM1/Orai1 na regulação das concentrações de Ca2+ citoplasmático e na ativação da contração vascular em aortas de ratos hipertensos. Nossos resultados sugerem que a ativação de STIM1/Orai1 pode representar um novo mecanismo que modula alterações vasculares nos níveis de Ca2+ intracelular na hipertensão arterial e que contribui para as diferenças sexuais de reatividade vascular em animais hipertensos. / Disturbance in the regulation of cytoplasmic calcium (Ca2+) concentration contributes to the pathogenesis of hypertension. Evidences suggest that the stromal interaction molecule (STIM) acts as a sensor of intracellular Ca2+ stores, whereas Orai proteins are the subunits that form CRAC channels. In this study, we evaluated the role of STIM1/Orai1 in the regulation of cytoplasmic Ca2+ concentrations and in the activation of contraction in aortas from hypertensive rats. We also studied how the differential activation of this pathway contributes to sex differences observed between hypertensive rats, as well as the protective effects of the female sex hormones in the vasculature. Our results suggest that activation of STIM1/Orai1 may represent a new mechanism that modulates intracellular Ca2+ concentration during hypertension and contributes to sex differences in the vascular reactivity of hypertensive animals.

Os distúrbios na regulação da concentração de cálcio (Ca2+) citoplasmático contribuem para a patogênese da hipertensão arterial. Evidências sugerem que as moléculas de interação estromal (STIM) atuam como sensores dos estoques intracelulares de Ca2+, enquanto as proteínas Orai representam as subunidades que formam os canais de Ca2+ ativados pela liberação de Ca2+ (CRAC). Neste estudo avaliamos a participação de STIM1/Orai1 na regulação das concentrações de Ca2+ citoplasmático e na ativação da contração vascular em aortas de ratos hipertensos. Nossos resultados sugerem que a ativação de STIM1/Orai1 pode representar um novo mecanismo que modula alterações vasculares nos níveis de Ca2+ intracelular na hipertensão arterial e que contribui para as diferenças sexuais de reatividade vascular em animais hipertensos. / Disturbance in the regulation of cytoplasmic calcium (Ca2+) concentration contributes to the pathogenesis of hypertension. Evidences suggest that the stromal interaction molecule (STIM) acts as a sensor of intracellular Ca2+ stores, whereas Orai proteins are the subunits that form CRAC channels. In this study, we evaluated the role of STIM1/Orai1 in the regulation of cytoplasmic Ca2+ concentrations and in the activation of contraction in aortas from hypertensive rats. We also studied how the differential activation of this pathway contributes to sex differences observed between hypertensive rats, as well as the protective effects of the female sex hormones in the vasculature. Our results suggest that activation of STIM1/Orai1 may represent a new mechanism that modulates intracellular Ca2+ concentration during hypertension and contributes to sex differences in the vascular reactivity of hypertensive animals.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-24T15:40:23Z No. of bitstreams: 1 CAROLINE MARTINEZ.pdf: 15483260 bytes, checksum: 336be2ac82e6f35a3e3945f6a2b3b533 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-24T15:48:42Z (GMT) No. of bitstreams: 1 CAROLINE MARTINEZ.pdf: 15483260 bytes, checksum: 336be2ac82e6f35a3e3945f6a2b3b533 (MD5) / Made available in DSpace on 2018-09-24T15:48:42Z (GMT). No. of bitstreams: 1 CAROLINE MARTINEZ.pdf: 15483260 bytes, checksum: 336be2ac82e6f35a3e3945f6a2b3b533 (MD5) Previous issue date: 2017-12-13 / O Alumínio (Al) é o metal de maior exposição humana, no entanto os efeitos do metal em nível de exposição humana ainda são pouco conhecidos. Assim, o objetivo desse estudo foi investigar os efeitos da exposição ao Al por 60 dias em dose equivalente a exposição humana ao metal através da dieta sobre o Sistema Nervoso Central (SNC), Sistema Nervoso Periférico (SNP), sistema reprodutor masculino e sistema cardiovascular e, comparar com os efeitos de uma exposição alta ao metal com efeitos tóxicos conhecidos. Para isso, ratos Wistar com 3 meses de idade foram divididos em: 1) Grupo 1: baixas doses de Al, onde durante 60 dias os ratos receberam por água de beber: a) Controle – água ultrapura; b) Al na dose de 1,5 mg/kg de peso corporal e, c) Al na dose de 8,3 mg/kg de peso corporal e, 2) Grupo 2: alta dose de Al, onde durante 42 dias os ratos receberam por gavagem: a) Controle – água ultrapura; b) Al na dose de 100 mg/kg de peso corporal. O tratamento com Al mesmo em baixas doses prejudicou a memória de reconhecimento de objetos e promoveu o desenvolvimento de catalepsia nos ratos. Somado a isso, a exposição ao Al aumentou os níveis de espécies reativas de oxigênio (EROs) e de peroxidação lipídica, reduziu a capacidade antioxidante e inibiu a atividade da acetilcolinesterase no hipocampo dos animais. No SNP, o Al promoveu o desenvolvimento de alodínea mecânica, aumentou o estresse oxidativo sistêmico, induziu inflamação com recrutamento de macrófagos e, o metal foi capaz de depositar-se entre as fibras do nervo ciático. Já no sistema reprodutor masculino, a exposição ao Al reduziu a contagem espermática, a motilidade e a produção diária de espermatozides, aumentou a porcentagem de espermatozoides com anormalidades morfológicas, alterou a estrutura testicular, aumentou os níveis de estresse 14 oxidativo e a inflamação testicular, demonstrando que uma baixa concentração do metal nos testículos (3.35 μg/g) é o suficiente para comprometer a espermatogênese e a qualidade dos gametas masculinos. No sistema cardiovascular, o Al aumentou a pressão arterial sistólica, reduziu a resposta vasodilatadora a acetilcolina, aumentou a resposta vasoconstritora a fenilefrina, reduziu a modulação endotelial na resposta vasoconstritora, reduziu a biodisponibilidade de óxido nítrico, o envolvimento dos canais de potássio nas respostas vasculares e aumentou a produção de EROs principalmente via NAD(P)H oxidase e de prostanóides contráteis da via da COX-2. A exposição ao Al aumentou o estresse oxidativo em artérias aorta e mesentérica, reduziu a expressão de mRNA de eNOS e SOD1 e aumentou a expressão da isoforma da NAD(P)H oxidase 1, COX-2 e a expressão de TXA-2 R. Tomados em conjunto, nossos dados demonstram que a exposição subcrônica ao Al por 60 dias em baixa dose, que reflete a exposição humana ao metal através da dieta, alcança um limiar tóxico suficiente para promover efeitos adversos no SNC, SNP, sistema reprodutor masculino e sistema cardiovascular. Além disso, os efeitos de uma exposição em baixa dose são praticamente os mesmos de uma exposição alta ao metal. / Aluminum (Al) is the most important environmental and human contaminant. While a good deal of research has been conducted on the acute toxic effects of Al, little is known about the effects of longer-term exposure at human dietary Al levels. Therefore, the purpose of this study was to investigate the effects of 60-day Al exposure at low doses on Central Nervous System (CNS), Peripheral Nervous System (PNS), male reproductive system and cardiovascular system for comparison with a model of exposure known to produce toxicity in rats. Three-month-old male Wistar rats were divided into two major groups: 1) Grou 1, low aluminum levels - rats were treated orally by drinking water for 60 days as follows: a) Control – received ultrapure drinking water; b) Aluminum at 1.5 mg/kg b.w. and c) Aluminum at 8.3 mg/kg b.w. and 2) Group 2, high aluminum level - rats were treated through oral gavages for 42 days as follows: a) Control – received ultrapure water; b) Aluminum at 100 mg/kg b.w. Al treatment even at low doses promoted recognition memory impairment seen in object recognition memory testing and catalepsy behavior in rats. Moreover, Al increased hippocampal reactive oxygen species (ROS) and lipid peroxidation levels, reduced antioxidant capacity and decreased acetylcholinesterase activity. On PNS, Al promoted the development of mechanical allodynia, increased inflammation in the sciatic nerve, systemic oxidative stress and, is able to be retained in the sciatic nerve. Regarding the male reproductive system, Al decreased sperm count, daily sperm production, sperm motility, normal morphological sperm, impaired testis histology; increased oxidative stress in reproductive organs and inflammation in testis, showing that low concentrations of Al in testes (3.35 μg/g) are sufficient to impair 16 spermatogenesis and sperm quality. On cardiovascular system, Al increased systolic blood pressure, decreased acetylcholine-induced relaxation, increased response to phenylephrine, decreased endothelial modulation of vasoconstrictor responses, the bioavailability of nitric oxide, the involvement of potassium channels on vascular responses, as well as increased ROS production from NAD(P)H oxidase and contractile prostanoids mainly from COX-2 in both aorta and mesenteric resistance arteries (MRA). Al exposure increased vascular ROS production and lipid peroxidation as well as altered the antioxidant status in aorta and MRA. Al decreased vascular eNOS and SOD1 mRNA levels and increased the NAD(P)H oxidase 1, COX-2 and TXA-2 R mRNA levels. Taken together, our data demonstrate that 60-day subchronic exposure to low doses of Al from feed and added to the water, which reflect human dietary Al intake, reaches a threshold sufficient to promote adverse effects on SNC, PNS, male reproductive system and cardiovascular system. Moreover, these effects were almost the same as Al exposure at much higher levels.

La gravité est un facteur environnemental majeur. C’est cette force qui a façonné la vie et le fonctionnement de notre organisme est intimement lié à la gravité. Pour rester en bonne santé, nous devons bénéficier de l’influence quotidienne de la gravité et d’un apport alimentaire adapté à notre activité physique. L’objectif de ce travail de thèse est d’étudier le remodelage vasculaire et la dysfonction endothéliale dans des modèles de sédentarité et de troubles métaboliques ainsi que d’explorer des moyens de contre mesures. Un alitement de 60 jours chez des sujets sains masculins induit un remodelage de la macrocirculation au niveau de l’artère fémorale ainsi qu’une dysfonction endothéliale au niveau de la microcirculation. La prise quotidienne d’extraits végétaux complexes issus de la médecine traditionnelle chinoise (Taikong Yangxin) a permis de prévenir l’atteinte endothéliale.Dans un modèle de rat diabétique avec atteinte vasculaire (rats GK),nous avons testé le salidroside, important composé issus du Taikong Yangxin. Bien qu’il n’ait pas d’effets sur le diabète, cecomposé a montré un effet bénéfique sur la vasodilatation endothéliale -dépendante et -indépendante. Dans une dernière partie nous avons étudié chez la souris l’implication du récepteur de type 2 à l’angiotensine et des récepteurs aux estrogènes dans les dysfonctions cardiovasculaires induite par une alimentation hypercalorique. L’inactivité physique induit un remodelage morphologique et fonctionnel au niveau de l’arbre vasculaire ce qui en fait un facteur de risque majeur et indépendant des maladies cardio-vasculaires. Des extraits végétaux simples ou complexes ont des effets bénéfiques sur les fonctions endothéliales. Le récepteur de type 2 à l’angiotensine et ses interactions possibles avec le récepteur aux oestrogènes pourrait être une cible pharmacologique comme contre mesure des atteintes vasculaires liées à l’environnement. / Gravity is a major environmental factor. This force that shaped the life and the functioning of our body is closely related to gravity. To remain healthy, we should benefit from the daily influence of gravity and a food intake adapted to our physical activity. The objective of this thesis is to study vascular remodeling and endothelial dysfunction in sedentary models and metabolic disorders and to explore ways of countermeasures. 60 days of head down bed rest in healthy male induce a macrocirculation remodeling at the femoral artery and an endothelial dysfunction at the microcirculation level. Daily intake of complex plant extracts from traditional Chinese medicine (Taikong Yangxin) helped to prevent endothelial dysfunction. In a diabetic rat model with vascular dysfunction (GK rats), we tested the salidroside, an important compound from the Taikong Yangxin. Although it has no effect on diabetes, this compound showed a beneficial effect on endothelial -dependent and -independent vasodilation. In the last part of our work, we studied the involvement of type 2 angiotensin receptor and estrogen receptor in cardiovascular dysfunction induced by a high calorie diet in mice. Physical inactivity induces morphological and functional remodeling in the vascular tree, making it a major risk factor independent of cardiovascular diseases. Simple or complex plant extracts have beneficial effects on endothelial function. Angiotensin type 2 receptor and its interaction with the estrogen receptor could be a pharmacological target as a countermeasure against vascular damage related to the environment.