Orientador: Winston Bonetti Yoshida / Coorientador: Ricardo de Alvarenga Yoshida / Resumo: Contexto: O clampeamento infrarrenal e trauma cirúrgico estão associados a alterações hemodinâmicas e oxidativas que podem comprometer a função renal pós-operatória. Ademais, a colite isquêmica é uma grave complicação da cirurgia da aorta abdominal. É possível que ocorram diferenças na fisiopatologia destas complicações associadas às diferentes modalidades de tratamento do aneurisma de aorta abdominal. Objetivo: Avaliar o estresse oxidativo, os distúrbios hemodinâmicos, lesão renal e as alterações histopatológicas em fragmentos de cólon esquerdo de porcos submetidos a modelo experimental de interrupção aguda de fluxo sanguíneo aórtico, comparando os diferentes acessos cirúrgicos: tradicional, endovascular ou videolaparoscópico. Material e Métodos: 30 porcos, fêmeas, com 15-30kg, foram divididos aleatoriamente em 3 grupos, sendo todos submetidos, sob anestesia geral inalatória, a interrupção de fluxo da aorta abdominal por 60 minutos, por diferentes técnicas: Grupo C (n=10), através de laparotomia transperitoneal; Grupo L (n=10), através da técnica totalmente laparoscópica; Grupo EV(n=10), através da via endovascular por insuflação de balão de oclusão de aorta. Foi feita monitorização intraoperatória de pressão arterial, frequência cardíaca, balanço hídrico e coleta de amostras de sangue antes do procedimento e 60 minutos após a reperfusão. Os desfechos primários estudados foram: volume de sangramento, estresse oxidativo sistêmico (dosagens de Malondialdeido, Glutationa Reduzi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Context: Infrarenal aortic cross-campling and surgical trauma are associated with hemodynamic and oxidative alterations that may impair postoperative renal function. Furthermore, Colonic ischemia is a relatively uncommon but devastating complication of abdominal aortic surgery. Its occurrence and severity is related to operative and anesthetic trauma. Therefore, it is a known complication of all different modalities of treatment of abdominal aortic aneurysm. Objective: To evaluate oxidative stress, hemodynamic disorders, renal injuries and histopathological changes in the left colon fragments of pigs subjected to the experimental model of acute aortic flow interruption, comparing the approaches by laparotomy, endovascular surgery and laparoscopic surgery. Materials and Methods: A total of 30 female pigs weighing 15-30 kg were randomly divided into 3 groups, all of which were subjected, under general ihaling anesthesia, to a 60-minute interruption of abdominal aortic flow by means of different techniques: C Group (n=10), through transperitonial laparotomy; L Group (n=10), through a totally laparoscopic technique; EV Group (n=10), through the endovascular procedures by insufflating the occlusion balloon of the aorta. Blood pressure, heart beat, and water balance intraoperative monitoring was performed and blood samples were collected both before the procedure and 60 minutes after reperfusion. The primary outcomes studied were: bleeding volume, systemic oxidative stress (levels... (Complete abstract click electronic access below) / Doutor

[pt] Aneurisma arterial é definido como uma dilatação excessiva do diâmetro normal de uma artéria. O aneurisma da aorta ascendente é geralmente assintomático, portanto, é frequentemente identificado acidentalmente durante exames de imagem de rotina. Após a identificação do aneurisma, caso não haja indicação cirúrgica, o paciente deve ser acompanhado de maneira adequada, pois a ruptura arterial pode ser fatal. A influência do fluxo sanguíneo no remodelamento aórtico é uma importante área de investigação. O objetivo deste estudo é identificar padrões hemodinâmicos em aneurismas de aorta ascendente que possam estar relacionados com o aumento do aneurisma. Cada paciente do estudo foi avaliado em dois momentos distintos. Um modelo tridimensional do aneurisma de aorta ascendente foi gerado para cada paciente a partir de exames de angiotomografia de aorta. O padrão de fluxo foi determinado numericamente com a utilização de um software comercial. Foi demonstrado que o ângulo entre a entrada do fluxo principal e o tronco braquiocefálico pode induzir a uma incidência de um jato incidente na parede da aorta, ocasionado áreas de recirculação na região posterior do jato, além de altos valores de pressão e tensão cisalhante. Os presentes achados hemodinâmicos podem estar relacionados com o remodelamento da aorta ascendente. / [en] Arterial aneurysmal is defined as an excessive dilation of the normal diameter of an artery. Ascending aortic aneurysm is generally asymptomatic, so it is often accidentally identified during routine imaging examinations. After the aneurysm has been identified, if there is no surgical indication, the patient should be followed adequately, since arterial rupture can be fatal. The influence of blood flow on aortic remodeling is an important area of investigation. The aim of this study is to identify hemodynamic patterns in ascending aortic aneurysms that may be related to aneurysm enlargement. Each patient in the study was evaluated at two different times. A three-dimensional model of the ascending aortic aneurysm was generated for each patient from aortic angiotomography examinations. The flow field was numerically determined with a commercial software. It has been shown that the angle between the entrance of the main flow and the brachiocephalic trunk can induce an incident jet on the aortic wall, causing areas of recirculation in the posterior region of the jet, besides high values of pressure and wall shear stress. The present hemodynamics findings may be related to remodeling of the ascending aorta.

published_or_final_version / Community Medicine / Master / Master of Public Health

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

This project focused on extracellular signal-regulated kinase (ERK) and focal adhesion proteins related to ERK activity, and found a novel signaling pathway contributing to aging-related defects in smooth muscle contractility. Previous members of our lab have used ERK inhibitors to demonstrate the role of ERK in smooth muscle contraction. Dr. Nicholson used the ERK inhibitor FR 18024 and noted that, in the presence of this inhibitor phenylephrine (PE) induced a higher stress increase in young mouse aortas compared to old aortas. Inhibition of the kinase ERK abolished this difference. He also quantitated ERK phosphorylation, a marker of ERK activation in PE-stimulated aortas from both young and aged mice and found a significant lower level of phosphorylated-ERK (p-ERK) in aged mouse aortas. I was interested in determining the substrate of ERK that is affected in aging. Caldesmon (CaD) is one of the known substrates of ERK in smooth muscle. More importantly, CaD, as an actin-binding protein, inhibits cross-bridge formation by blocking the interaction between actin and myosin. Thus, I tested the hypothesis that, caldesmon phosphorylation is inhibited in aged mouse aortas. To determine the mechanism by which regulation of ERK activation changes with age, the role of micro-RNAs (miRs) in the regulation ERK phosphorylation was investigated. Transfection of miR-137 and -34a into A7r5 cells resulted in a significantly lower level of p-ERK in response to the phorbol ester DPBA. Further, together with my collaborators I found that transfection of miR-137 and -34a led to significantly decreased focal adhesion protein levels in A7r5 smooth muscle cells, such as paxillin and src. To confirm whether focal adhesion proteins contribute to the impairment of agonist-induced ERK phosphorylation, paxillin siRNA and src inhibitor were used. The results showed that paxillin is required for the phosphorylation of ERK1 and ERK2 and src is required for ERK2 phosphorylation. In conclusion, age-related increases in miR-137 and -34a decrease ERK phosphorylation via downregulation of paxillin and src. The decrease in ERK phosphorylation leads to a decrease in CaD phosphorylation and inhibits contraction. Thus, the thin filament-coupled pathway in differentiated vascular smooth muscle is inhibited in the aged mouse aorta and this leads to aging-associated defects in smooth muscle contractility. / 2021-06-18T00:00:00Z

Bakgrund: Att vänta på en elektiv operation förknippas med upplevelser av depression och oro. Patienter med aortaaneurysm uttrycker att sjukdomen bidrar till begränsningar i livet, trots avsaknad av fysiska symtom. Informationen anses också vara bristfällig innan operationen samt att det är svårt att få kontakt med sjukvården för att kunna ställa frågor. Syfte: Syftet var att beskriva patienters upplevelser av att vänta på en operation av aortaaneurysm eller aortadissektion samt utröna vilket stöd som behövs för att underlätta väntan för dessa patienter. Metod: En kvalitativ intervjustudie utfördes med tio informanter som genomgått elektiv operation av aortaaneurysm eller aortadissektion. En manifest innehållsanalys utfördes. Resultat: Informanterna beskrev både positiva och negativa aspekter under väntan inför operation. Detta kunde exempelvis vara att det både fanns känslor av oro men även känslor av lugn under väntan. Även påverkan på livet ansågs vara liten respektive stor där det till exempel upplevdes svårt att planera för aktiviteter. Den information som levererades ansågs vara både tillfredsställande och otillräcklig. Slutsats: Det finns ett behov av att patienter som väntar på en operation av aortaaneurysm eller aortadissektion får korrekt information. Genom att utveckla en organisationskultur som tillåter ett individuellt anpassat stöd där all vårdpersonal har ett ansvar kan det förbättra välmåendet hos dessa patienter.

INTRODUÇÃO: O tratamento endovascular das doenças da aorta é modalidade consagrada atualmente, sendo realizado em indivíduos jovens e idosos, tanto na aorta torácica quanto na abdominal. Esta terapia baseia-se numa interação adequada entre a endoprótese e a parede aórtica. Neste sentido, o conhecimento do comportamento biomecânico da aorta é fundamental. A aorta humana é uma estrutura complexa, com comportamento biomecânico diferente de acordo com a idade, a região e a presença de doenças. Estudos com biomecânica da aorta humana não aneurismática são escassos. OBJETIVOS: Analisar os parâmetros biomecânicos de falência e as características histológicas da aorta torácica e abdominal humana, correlacionando-os com idade e gênero. MÉTODO: Testes destrutivos uniaxiais de espécimes removidos de 26 aortas frescas de cadáveres foram realizados num aparelho de tração universal. Os parâmetros biomecânicos de falência avaliados foram: força, tensão, estresse, deformação e energia de deformação. Foi realizado estudo histológico do tecido aórtico para quantificação de fibras colágenas, musculares e elásticas. RESULTADOS: Foram analisados os testes biomecânicos válidos de 153 espécimes, sendo 95 da aorta torácica e 58 da aorta abdominal. Na comparação entre aorta torácica e abdominal, realizada por análise de variância, foi observado que diâmetro (30,45 versus 23,99 mm; p < 0,001), espessura (1,69 versus 1,44 mm; p < 0,001), força máxima (6,18 versus 4,85 N; p = 0,001), tensão de falência (19,88 versus 14,53 N/cm; p = 0,001), deformação de falência (0,66 versus 0,49; p = 0,003) e a percentagem de fibras elásticas (19,39 versus 14,06 %; p = 0,011) foram maiores, com significância, na aorta torácica. As correlações de Spearman entre idade e força máxima, estresse de falência, tensão de falência, deformação de falência e energia de deformação foram negativas e significativas na aorta torácica e abdominal. As aortas do sexo masculino, através do teste t de Student, apresentaram maior força máxima e tensão de falência. Não houve diferença na composição histológica entre os gêneros. CONCLUSÕES: A aorta torácica é mais resistente e elástica que a aorta abdominal. O conteúdo de fibras elásticas é maior na aorta torácica. Os idosos apresentam aortas menos resistentes e mais rígidas que os jovens. A aorta do sexo masculino é mais resistente / INTRODUCTION: The endovascular repair of aortic diseases is currently widely performed among young and elderly patients, in both the thoracic and abdominal aorta. This treatment is based on an appropriate interaction between the stent graft and the aortic wall. Thus, it is essential to understand the biomechanical behavior of the aorta. The human aorta is a complex vessel with different biomechanical behaviors according to age, location and diseases. There are few biomechanical studies of the human nonaneurysmal aorta. OBJECTIVES: To analyze the biomechanical properties and histological composition of the human aorta according to age and gender. METHODS: Twenty-six human aortas were harvested whole from fresh cadavers during their autopsies. Each aorta was cut into strips for mechanical testing. Uniaxial tensile tests were performed on a tensile-testing machine. The failure load, failure stress, failure tension, failure strain and strain energy were calculated. A histological study was performed to measure the amount of collagen, elastin and smooth muscle cells in the aortic wall. RESULTS: A total of 153 strips were studied (95 from the thoracic aorta and 58 from the abdominal aorta). The diameter (30.45 versus 23.99 mm; p < 0.001), thickness (1.69 versus 1.44 mm; p < 0.001), failure load (6.18 versus 4.85 N; p = 0.001), failure tension (19.88 versus 14.53 N/cm; p = 0.001), failure strain (0.66 versus 0.49; p = 0.003) and elastin amount (19.39 versus 14.06 %; p = 0.011) were all significantly higher for the thoracic aorta than for the abdominal aorta. There was a significant negative Spearman\'s correlation between age and failure load, failure stress, failure tension, failure strain and strain energy. Male aortas had a higher failure load and failure tension than female aortas. No difference in the histological composition was found between the genders. CONCLUSIONS: The thoracic aorta has a higher strength and elasticity than the abdominal aorta. The elastin amount is higher in the thoracic aorta than in the abdominal aorta. The elderly have weaker and stiffer aortas than the young. Male aortas have a higher strength than female aortas

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Oncostatin M (OSM) is a cytokine of the interleukin-6 family and released in the early phase of inflammation by neutrophils, activated macrophages, dendritic cells, and T lymphocytes. Its roles in physiology and disease are not entirely understood yet. It has been shown recently that substantial amounts of OSM are found in atherosclerotic plaques. The first part of this thesis addresses the effects of OSM on vascular smooth muscle cells (VSMCs). This cell type is known to contribute to atherogenesis and expresses the type I and type II OSM receptor complexes. This study revealed that OSM is a strong inducer of an array of genes which have recently been shown to play important roles in atherosclerosis. Investigation of VSMCs isolated from OSMRbeta-deficient (Osmr-/-) mice proved that the regulation of these target genes is entirely dependent on the activation of the type II OSMR complex. In addition to OSM, other cytokines expressed by T lymphocytes were found to contribute to plaque development. According to earlier publications, the influence of IL-4, IL-13, and IL-17 on the progression of plaques were discussed controversially. Nevertheless, for the regulation of investigated atherosclerotic target genes and receptor complexes in VSMCs, they seemed to play a minor role compared to OSM. Only the expression of the decoy receptor IL-13Ralpha2 - a negative feedback mechanism for IL-13-mediated signalling - was strongly induced after treatment with all mentioned cytokines, especially when VSMCs were primed with OSM before stimulation. The second part of this thesis focuses on the role of OSM during the progression of atherosclerosis in vivo. Therefore, Ldlr-/-Osmr-/- mice were generated by crossing Ldlr-/- mice - a typical mouse model for atherosclerosis - with Osmr-/- mice. These double-deficient mice together with Ldlr-/-Osmr+/+ mice were set on cholesterol rich diet (Western diet, WD) for 12 weeks before they were sacrificed. Determination of body and organ weight, staining of aortas and aortic roots as well as gene expression profiling strongly suggested that Ldlr-/-Osmr-/- mice are less susceptible for plaque development and weight gain compared to Ldlr-/-Osmr+/+ mice. However, further experiments and additional controls (C57Bl/6 and Osmr-/- mice) on WD are necessary to clarify the underlying molecular mechanisms. Taken together, the interleukin-6-type cytokine OSM is a strong inducer of an array of target genes involved in de-differentiation and proliferation of VSMCs, a process known to contribute substantially to atherogenesis. Further in vivo studies will help to clarify the role of OSM in atherosclerosis. / Oncostatin M (OSM) gehört zur Familie der Interleukin-6-Typ Zytokine und wird in der frühen Phase der Inflammation von Neutrophilen, aktivierten Makrophagen, dendritischen Zellen und T-Lymphozyten freigesetzt. Seine Rolle in der Physiologie und Erkrankung ist noch nicht gänzlich verstanden. Vor kurzem konnte gezeigt werden, dass eine wesentliche Menge an OSM in arteriosklerotischen Plaques vorhanden ist. Der erste Teil dieser Dissertation thematisiert den Effekt von OSM auf vaskuläre glatte Muskelzellen (vascular smooth muscle cells, VSMCs). Dieser Zelltyp trägt zur Entstehung der Arteriosklerose bei und exprimiert sowohl den Typ I als auch den Typ II OSM Rezeptor-Komplex. Diese Studie zeigt, dass OSM ein starker Induktor einer Reihe von Genen ist, von denen kürzlich gezeigt wurde, dass sie eine wichtige Rolle in der Arteriosklerose spielen. Eine Untersuchung an VSMCs, isoliert aus OSMRbeta- defizienten (OSMR-/-) Mäusen, bewies, dass die Regulation der Zielgene gänzlich von der Aktivierung des Typ II OSMR-Komplexes abhängig ist. Neben OSM wurden auch andere, von T-Lymphozyten exprimierte Zytokine gefunden, die zur Entwicklung von Plaques beitragen. Laut vorheriger Publikationen wurde der Einfluss von IL-4, IL- 13 und IL-17 auf die Plaqueprogression kontrovers diskutiert. Dennoch scheinen diese Zytokine verglichen mit OSM für die Regulation der hier untersuchten, arteriosklerotischen Zielgene und Rezeptorkomplexe in VSMCs nur eine untergeordnete Rolle zu spielen. Lediglich die Expression des Köderrezeptors (decoy receptor) IL-13Ralpha2, der eine negative Rückkopplung der IL-13 vermittelten Signaltranduktion darstellt, wurde durch die Behandlung mit den oben genannten Zytokinen stark induziert. Dies geschieht insbesondere dann, wenn VSMCs vor der Stimulation mit OSM vorbehandelt wurden. Der zweite Teil befasst sich mit der Rolle des OSM während der Enstehung von Arteriosklerose in vivo. Hierfür wurden Ldlr-/-Osmr-/- Mäuse durch Kreuzung von Ldlr-/- - einem typischen Mausmodell für Arteriosklerose - mit Osmr-/- Mäusen generiert. Diese doppeldefizienten Mäuse zusammen mit Ldlr-/-Osmr+/+ Mäusen wurden für 12 Wochen auf eine cholesterinreiche Diät (Western diet, WD) gesetzt bevor sie geopfert wurden. Die Bestimmung des Körpergewichts und des Gewichts der Organe, das Anfärben der Aorten und der Aortenwurzeln sowie das Erstellen eines Gen-Expressionsprofils wies stark darauf hin, dass Ldlr-/-Osmr-/- Mäuse weniger anällig für die Ausbildung von Plaques und eine Gewichtszunahme sind als Ldlr-/-Osmr+/+ Mäuse. Dennoch sind weitere Experimente und zusätzliche Kontrollen (C57Bl/6 und Osmr-/- Mäuse) nötig, um die zugrundeliegenden, molekularen Mechanismen aufzuklären. Zusammenfassend ist das Interleukin-6-Typ Zytokin OSM ein starker Induktor einer Reihe an Zielgenen, die an der De-differenzierung und Proliferation von VSMCs beteiligt sind. Dieser Prozess könnte wesentlich zur Arteriogenese beitragen. Weitere in vivo Experimente werden helfen die Rolle des OSM in der Arteriosklerose zu verstehen.

The vascular system transports components essential to the survival of the individual and acts as a barrier to substances that may injure the organism. Atherosclerosis is a dynamic, lesion producing disease of the arterial system that compromises the functioning of the organ by occlusive and thrombogenic processes. This investigation was undertaken to elucidate some of the normal biochemical processes related to the development of atherosclerosis. A significant part of the investigation was directed toward developing and combining methods and protocols to obtain the data in a concerted manner. A postmitochondnal supernatant of bovine aorta, using mevalonate-2-�����C as the substrate, was employed in the investigation. Methods included paper, thin layer, and silica gel chromatography; gel filtration, high performance liquid chromatography (HPLC), and mass spectrometry. This current research demonstrated direct incorporation of mevalonate-2- �����C into the trans-methyiglutaconic shunt intermediates. The aorta also contains alcohol dehydrogenase activity, which converts dimethylallyl alcohol and isopentenol to dimethylacrylic acid, a constituent of the trans-methylgiutaconate Small, radioactive peptides, named Nketewa as a group, were biosynthesized using mevalonate-2-�����C as the substrate. They were shown to pass through a 1000 D membrane. Acid hydrolysis and dabsyl-HPLC analysis defined the composition of the Nketewa peptides. One such peptide, Nketewa 1, had a molecular weight of 1038 and a sequence of his-gly-val-cys-phe-ala-ser-met (HGVCFASM), with a farnesyl group linked via thioether linkage to the cysteine residue. Methods were developed for the concerted investigation of the trans-methylglutaconate shunt, the isolation of mevalonate-2-�����C labeled peptides, and characteristics of neutral and acidic metabolites of mevalonate. The question as to whether or not mevalonate was the direct precursor was answered in the affirmative. These results contribute to the understanding of the biochemistry of the vessel wall and the associated atherogenic processes. Mevalonate-derived volatile and acidic compounds may represent an alternate metabolic pathway. The prenylated Nicetewa peptide may be, as are other prenylated peptides, participants in the intracellular signaling process, release of cytokines, expansion of extracellular matrix, and calcium release. / Graduation date: 2001