INTRODUÇÃO: A hipertensão pulmonar (HP) é comorbidade frequente em pacientes com insuficiência cardíaca (IC) e está associada ao pior prognóstico no pós-transplante cardíaco (TC). O teste de reatividade pulmonar realizado no préoperatório de TC avalia a reversibilidade da HP aos vasodilatadores, uma vez que a HP reversível tem melhor prognóstico. O nitroprussiato de sódio (NPS) é o vasodilatador mais utilizado, porém é associado a elevados índices de hipotensão arterial sistêmica, disfunção ventricular do enxerto transplantado e elevadas taxas de desqualificação para o TC. O sildenafil (SIL) é um inibidor seletivo da fosfodiesterase tipo 5 e utilizado no tratamento da HP idiopática, sem promover efeitos sistêmicos negativos. Neste estudo, objetivou-se avaliar os efeitos hemodinâmicos agudos do SIL e NPS sobre a HP de candidatos ao TC e seus efeitos sobre o remodelamento cardíaco reverso, definido como redução dos diâmetros ventriculares e melhora da função cardíaca, por meio da análise ecocardiográfica, hemodinâmica e bioquímica. MÉTODOS: Os pacientes foram submetidos, simultaneamente, ao cateterismo cardíaco direito para medida das pressões pulmonares, ao ecocardiograma, à dosagem sanguínea de BNP e à gasometria venosa, prosseguindo no estudo caso preenchessem os critérios de inclusão previamente estabelecidos. Os pacientes selecionados foram randomizados a receber NPS (1 - 2 ?g/Kg/min) ou SIL (100mg, dose única, via oral) e, após o período de tempo predeterminado, procedeu-se à nova avaliação hemodinâmica, ecocardiográfica e bioquímica. RESULTADOS: NPS e SIL reduziram significativamente a pressão sistólica da artéria pulmonar (NPS: 64,7 vs. 57mmHg, p = 0,002; SIL: 61,07 vs. 50mmHg, p < 0,001), porém o grupo que recebeu NPS apresentou redução acentuada da média da pressão arterial sistêmica (85,2 vs. 69,8mmHg, p < 0,001). Do ponto de vista ecocardiográfico, ambas as medicações promoveram redução da área ventricular direita (NPS: 29,2 vs. 25,7mm, p = 0,003; SIL: 29,4 vs. 23,8mm, p < 0,001) e elevação da fração de ejeção ventricular esquerda (NPS: 23,5 vs. 24,8 %, p = 0,02; SIL: 23,8 vs. 26 %, p < 0,001). Por outro lado, o grupo que recebeu SIL, ao contrário do NPS, apresentou melhora no índice de saturação venosa de oxigênio, medido pela gasometria venosa (SIL: 49,2 vs. 58,9%, p < 0,001). Os vasodilatadores não interferiram de forma significativa nos níveis séricos de BNP. CONCLUSÃO: Sildenafil e nitroprussiato de sódio reduziram significativamente a hipertensão pulmonar de pacientes com IC avançada. Ambos estiveram associados ao remodelamento cardíaco reverso, com diminuição da área ventricular direita e melhora da função cardíaca, medidos por parâmetros hemodinâmicos, ecocardiográficos e bioquímicos. O NPS, ao contrário do SIL, esteve associado à significativa hipotensão arterial sistêmica e piora do índice de saturação venosa de oxigênio. / INTRODUCTION: Pulmonary hypertension (PH) is a common comorbidity in heart failure (HF) patients and is associated with poor post heart transplant (HT) prognosis. The pulmonary reactivity test performed pre-operatively to the HT evaluates the reversibility of the PH to the vasodilators, since a reversible PH has a better prognosis. Sodium nitroprusside (SNP) is the most widely used vasodilator, but is associated with higher rates of systemic arterial hypotension, ventricular dysfunction of the transplanted graft and higher rejection rates of the HT. Sildenafil (SIL) is a selective phosphodiesterase type 5 inhibitor and is used in the treatment of idiopathic PH, without producing negative systemic effects. This study aimed to evaluate the acute hemodynamic effects of SIL and SNP on the PH of HT candidates and their effects on reverse cardiac remodeling, defined as a reduction in ventricular diameter and improvement of cardiac function, through echocardiographic, hemodynamic and biochemical analysis. METHODS: The patients simultaneously underwent: right cardiac catheterization, to measure the pulmonary pressure, echocardiogram and blood dosage of BNP and venous gas analysis, continuing in the study if the previously established inclusion criteria were met. The selected patients were randomly given SNP (1 - 2 ?g/Kg/min) or SIL (100mg, single dose, orally) and after a predetermined period of time went for a new hemodynamic, echocardiographic and biochemical evaluation. RESULTS: SNP and SIL significantly reduced the systolic pulmonary artery pressure (SNP: 64.7 vs. 57mmHg, p = 0.002; SIL 61.07 vs. 50mmHg, p = 0.001). However the group which received SNP showed a marked reduction in mean systemic blood pressure (85.2 vs. 69.8mmHg, p < 0.001). From the point of view of the echocardiography, both the medications produced a reduction in right ventricular size (SNP: 29.2 vs. 25.7mm, p = 0.003; SIL 29.4 vs. 23.8mm, p < 0.001) and an increase of the left ventricular ejection fraction (NPS: 23.5 vs. 24.8 %, p = 0.02; SIL: 23.8 vs. 26 %, p < 0.001). On the other hand, the group which received SIL, unlike the SNP, showed improvements in the rate of oxygen venous saturation, measured by venous gas analysis (SIL: 49.2 vs. 58.9%, p < 0.001). Neither group significantly affected the serum levels of BNP. CONCLUSION: Sildenafil and sodium nitroprusside significantly reduced pulmonary hypertension in patients with advanced HF. Both were associated with reverse cardiac remodeling, with a reduction in right ventricular area and improvement of the cardiac function, measured by hemodynamic, echocardiographic and biochemical parameters. SNP, unlike SIL, was associated to significant systemic arterial hypotension and worsening of the rate of venous oxygen saturation.

A prevalência mundial de asma na infância é alta. Alterações estruturais das vias aéreas são observadas na asma, e podem ocorrer precocemente na infância. Este estudo tem como objetivo comparar os resultados de um modelo de sensibilização alérgica, em camundongos de diferentes idades. Para tanto foram utilizados camundongos Balb/C pré-desmamados, jovens e adultos. O grupo de animais pré desmamados foram divididos em outros dois grupos (18D 18D1), sendo que ambos foram sensibilizados com duas injeções intraperitoneal (i.p.) de 10 g ovalbumina (OVA) no 5º e 7º dia de vida. Após, o primeiro grupo de camundongos pré desmamados foram submetidos a 01 (um) desafio, este consistente em receberem inalações por 3 dias consecutivos, a 3% de OVA, por 10 minutos, nos dias 14, 15 e 16. O segundo grupo de camundongos pré desmamados foram submetidos 02 (dois) desafios, estes nos dias 09, 10 e 11; e 14, 15 e 16 dias de vida. O grupo de camundongos jovens (40D) receberam as mesmas inalações nos dias 22 a 24 e depois nos dias 36 a 38. Um quarto grupo de camundongos, denominados adultos (100D), foram sensibilizados com 10 g OVA i.p. nos dias 60 e 62 de vida; e também recebendo inalações por 3 dias consecutivos a 3% de OVA, por 10 minutos, nos dias 77 a 79 de vida, repetindo o procedimento nos dias 96, 97 e 98, sendo que os animais em todos os xiii grupos foram sacrificados 48hs após a última inalação. Todos os grupos possuíam um grupo controle respectivo, mesmo protocolo, mas ao invés de OVA, recebiam apenas solução salina. Observamos que os animais sensibilizados, quando comparados entre si, não apresentavam diferença quanto à densidade de células de eosinófilos (p = 0,052). A densidade de células TCD3+ foi maior nos camundongos adultos e no grupo de animais pré desmamados com dois desafios (p<0,001), não havendo diferença nos demais grupos (p=1,000). Foi possível observar também uma maior expressão de IL-5 nas vias aéreas quando comparados os grupos OVA de 18 dias de vida (18D e 18D1) com os seus controles (p=0,017). Todavia não houve esta diferença de IL-5 nos grupos jovens e adultos. Entre os grupos controles, a expressão de IL-5 foi menor nos grupos de 18 dias de vida (18D e 18D1) em relação aos animais dos grupos de 40 e 100 dias de vida (40D e 100D - p<0,001). Verificamos ainda que o grupo de animais pré desmamados com um desafio (p = 0,003) e os camundongos adultos (p = 0,006) apresentaram aumento da expressão de TGF- nas vias aéreas, quando comparados aos seus respectivos controles; e que os camundongos do grupo pré desmamado com um ou dois desafios apresentaram maior expressão de PAS no epitélio bronquiolar, quando comparado aos camundongos jovens e adultos (18D e 18D1 - p=0,007 e 40D e 100D - p=0,073). Entre os camundongos sensibilizados, o grupo pré desmamado com um único desafio, apresentou menor fração de área de colágeno comparado ao grupo de camundongos pré desmamados que receberam dois desafios (p<0,001), não havendo outras diferenças entre os grupos. xiv Camundongos jovens e adultos apresentaram um aumento de espessura do músculo liso da via aérea (MLB) quando comparados a seus respectivos controles (p = 0,048). Desta forma, foi possível demonstrar que os camundongos pré desmamados podem desenvolver alterações inflamatórias e estruturais nas vias aéreas, porém apresentam características diferentes das alterações observadas em animais com maior idade. Por fim, conclui-se que o presente estudo proporciona resultado e forma a ser utilizado como base para um estudo experimental, seja para verificar o resultado de medicamentos, seja para um estudo comparativo em crianças, jovens e adultos com asma, a fim de se verificar as diferenças apresentadas; e assim, auxiliar na adequada conduta clínica para prevenção ou combate dessa doença / The prevalence of childhood asthma is high worldwide. Recent data indicate that asthma structural changes occur early in childhood, and that structure alterations occur early in life. In this study we have aimed to compare a model of allergic sensitization in infantile, juvenile and adult mice. BALB/c mice at different ages were sensitized with two intraperitoneal injections (i.p.) of 10 g ovalbumin (OVA) at day 05 and 07 and received 3 daily inhalations of 3% OVA for 10 min on days 14 to 16 and 09 to 11 - 14 to 16 the infantile groups (18d - 18d1).The juvenile mice (40d) at days 22 to 24 - 36 to 38 and adult mice (100d) were sensitized with 3% OVA i.p. at day 60 and 62 and received 2x 3 daily inhalations at days 77-79 and at day 96-98, being euthanized 48h later. Control groups received saline using the same protocols. The OVA treated animals were compared among each other there were no differences regarding eosinophil cell density (p= 0.052). The density of T CD3+ cells was higher in the adult mice and in the infantile group with two challenges in relation to 18D e 40D (p=0.000), but without differences between the former groups (p= 1.000). When OVA groups were compared to the respective controls, infantile groups presented increased IL-5 expression in the airways (p=0.017), no differences were observed in the juvenile and adult mice. Among controls, IL-5 expression was lower in the infantile groups in relation to the juvenile and adult mice (p<0.001). The infantile group (p=0.003) with one challenge and the adult mice (p=0.006) presented increased TGF- expression in the airways when compared to their respective controls. Infantile mice with one or two challenges presented more PAS positivity in the bronchiolar epithelium than the juvenile and adult mice (p=0.007 and p=0.073). Among the OVA mice, infantile mice with one xvi challenge presented lower collagen area fraction than the group of infantile mice that received two challenges (p=0.000), without further differences among groups. Juvenile and adult mice had increased ASM thickness when compared to their age related controls (p=0.48). In summary, we have shown that infantile mice develop inflammatory and structural alterations in the airways, but that are partially different from those developed in older animals. Understanding the phenotypic differences in children vs adult asthma is very important to treat disease adequately and to manage prevention of severity

O presente estudo foi realizado para investigar a relação entre forças hemodinâmicas locais e remodelamento intimal e medial nos segmentos pré-estenose e pós-estenose da parede da aorta abdominal de ratos submetidos à estenose acentuada. Foram utilizados ratos Wistar machos divididos em dois grupos: sham-operado, grupo controle em que a aorta foi apenas manipulada, e grupo estenosado, animais submetidos à cirurgia de estenose da aorta abdominal. As aortas demonstraram duas respostas remodeladoras distintas e diferentes ao estímulo hemodinâmico induzido pela coarctação infra-diafragmática. A primeira é o remodelamento no segmento pré-estenótico hipertensivo com tensão circunferencial da parede aumentada associada com estresse tensional normal, fluxo laminar e tensão de cisalhamento normal. As células endoteliais eram heterogêneas, aumentadas em tamanho e alongadas em direção ao fluxo. Além disso, observou-se conspícuas placas neointimais difusamente distribuídas e espessamento medial. Nossos achados sugerem que a tensão circunferencial da parede aumentada devido a hipertensão tem papel fundamental no remodelamento desse segmento através de efeitos biomecânicos sobre o estresse oxidativo e expressão aumentada de TGF-?. A segunda é o remodelamento no segmento pós-estenótico normotenso com fluxo turbilhonar e baixa tensão de cisalhamento na parede associados a tensão circunferencial da parede e estresse tensional normais. As células endoteliais apresentavam-se semelhantes aos controles, exceto por alterações fenotípicas focais associadas à presença de conspícuas placas neointimais focalmente distribuídas, similares mas muito maiores que as encontradas no segmento pré-estenose. Mais estudos são necessários para se determinar como as forças mecânicas do fluxo turbilhonar e da baixa tensão de cisalhamento na parede são detectadas e traduzidas em sinais bioquímicos para as células e convertidas em alterações fenotípicas patofisiologicamente relevantes. / The present investigation was carried out to evaluate the relationship between local hemodynamic forces and intimal and medial remodeling in the proximal and distal segments of the arterial walls of rats in relation to severe stenosis of the aorta. Male Wistar young rats were divided randomly into: operated group, animals submitted to surgical abdominal aorta stenosis, and sham-operated group, a control group of animals submitted to sham operation to simulate abdominal aorta stenosis. Constricted aortas showed two distinct adaptive remodeling responses to hemodynamic stimuli induced by coarctation. The first is remodeling in the hypertensive prestenotic segment with increased circumferential wall tension associated with normal tensile stress, laminar flow/normal wall shear stress. The remodeling in this segment is characterized by enlarged heterogeneous endothelial cells, elongated in the direction of the blood flow, diffusely distributed neointimal plaques, appearing as discrete bulging toward the vascular lumen, and medial thickening. Our findings suggest that increased circumferential wall tension due to hypertension play a pivotal role in the remodeling of the prestenotic segment through biomechanical effects on oxidative stress and increased TGF-? expression. The second is remodeling in the normotensive poststenotic segment with turbulent flow/low wall shear stress and normal circumferential wall tension and tensile stress. The remodeling in this segment is characterized by groups of endothelial cells with phenotypic alterations and focally distributed neointimal plaques, similar but many of them larger than those found in the prestenotic segments. Further studies are needed to determine how the mechanical forces of turbulent flow/low shear stress are detected and transduced into biochemical signaling by the cells of the artery walls and then converted into pathophysiologic relevant phenotypic changes.

No infarto, o remodelamento da região ventricular remota tem sido pouco examinado. Previamente, observamos que a redução da pressão de perfusão coronariana (PPC) associa-se ao aparecimento de fibrose subendocárdica. O objetivo do presente estudo foi investigar o papel da PPC no remodelamento e na função ventricular esquerda após o infarto. Medidas hemodinâmicas foram determinadas em ratos Wistar imediatamente após o infarto (IM) ou cirurgia fictícia (SH) e ao final dos seguimentos de 1, 3, 7, e 28 dias. Cortes teciduais do coração foram submetidos a coloração com HE, Sirius red, e a imunohistoquímica para a-actina. Duas regiões distintas do ventrículo esquerdo remotas ao infarto foram examinadas: subendocárdio (SE) e interstício (INT). A necrose de miócitos, a infiltração leucocitária e de miofibroblastos, e a fração de volume do colágeno foram determinadas. Comparados com SH, os grupos IM apresentaram menor PPC e disfunção sistólica e diastólica do ventrículo esquerdo. A necrose foi evidente em SE no dia 1. A inflamação e a fibroplasia ocorreram predominantemente em SE até o dia 7. A fibrose foi restrita a SE e evidente desde o dia 3. Em INT, a inflamação ocorreu predominantemente nos dias 1 e 3, mas em menor grau comparada a SE. A queda da PPC associou-se à dilatação progressiva do ventrículo esquerdo. Em SE, a PPC relacionou-se inversamente com a necrose (r =- 0,65, p = 0,003, no dia 1), com a inflamação (r = -0,76, p < 0,001, no dia 1), com a fibroplasia (r = -0,47, p = 0,04, no dia 7) e com a fibrose (r = -0,83, p < 0,001, no dia 28). A necrose no dia 1, a inflamação nos dias 3 e 7 e a fibroplasia no dia 7 relacionaram-se inversamente com a função do ventrículo esquerdo. A PPC é um fator determinante da integridade de SE e interfere com o remodelamento e a função do ventrículo esquerdo. / Left ventricular (LV) subendocardial remodeling has been poorly investigated after myocardial infarction. Previously, we have demonstrated that low coronary driving pressure (CDP) early in the course of infarction was associated with the subsequent development of subendocardial fibrosis. The present study aimed at the investigation of the role of CDP in LV remodeling and function following infarction. Hemodynamics were determined in Wistar rats immediately after infarct surgery (MI group) or sham (SH group) and at days 1, 3, 7, and 28. Heart tissue sections were stained with HE, Sirius red and immunostained for a- actin. Two distinct LV regions remote to MI were examined: subendocardium (SE) and interstitium (INT). Myocyte necrosis, leukocyte and myofibroblast infiltration, and collagen volume fraction were determined. Compared with SH, MI groups showed lower CDP and LV systolic and diastolic dysfunction. Necrosis was evident in SE at day 1. Inflammation and fibroplasia occurred predominantly in SE as far as day 7. Fibrosis was restricted to SE and was evident beginning from day 3. Inflammation occurred predominantly at days 1 and 3 in INT, but at a lower extent than in SE. CDP fall was associated with progressive LV dilatation. In SE, CDP correlated inversely with necrosis (r = -0.65, p=0.003, at day 1), inflammation (r = -0.76, p < 0.001, at day 1), fibroplasia (r = -0.47, p = 0.04, at day 7) and fibrosis (r = -0.83, p < 0.001, at day 28). Necrosis at day 1, inflammation at days 3 and 7, and fibroplasia at day 7 correlated inversely with LV function. CDP is a key factor to SE integrity following infarction and interferes with LV remodeling and function.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-29T14:15:55Z No. of bitstreams: 2 Dissertação Raphael.pdf: 2502185 bytes, checksum: 8f01f9c4d9e3e59032b2f45ae01ebd24 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-29T14:15:55Z (GMT). No. of bitstreams: 2 Dissertação Raphael.pdf: 2502185 bytes, checksum: 8f01f9c4d9e3e59032b2f45ae01ebd24 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-04-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The plasma vitamin D plays a key role in regulating calcium and phosphate homeostasis with activity on liver, intestine, kidney and bone. Calcium and phosphate obtained through the diet, are environmental elements necessary together with Vitamin D to determine whether 1,25-hydroxyvitamin D exerts an anabolic or catabolic effect on bone mineral appearance. This research was conducted to evaluate the effect of vitamin D3 supplementation exerts on the bone density of the femur and mice jaw. mice were used C57BL / 6 males and females, were divided into two groups: 1) control group (n = 24) and 2) experimental group (n = 24) - subject to systemic administration of vitamin D by means of vitamin D3 gavage (VITD) at a concentration of 10,000 IU for week. After 4 weeks of administration of Vitamin D was performed surgery for placement of titanium implants in the lateral region of the mandible and animals were sacrificed within 7 and 21 days after implant placement. Histomorphometric analyzes were carried out in the regions of femoral metaphysis and jaw through digital LAZ v4.2 and radiographic program and analyzed by BA-DDX program through digital periapical, where it was verified that there was an increase in bone density among the groups through the trabecular pixel count. For the statistical analysis were applied Anova and Bonferroni multiple correlation and Kruskal Wallis test. The results of histomorphometric analysis showed no difference in bone structures (trabecular and marrow spaces) in the jaw evaluated by vitamin D3 supplementation at 7 and 21 days of healing. The results of radiographic however, showed that the jaw was no increase in bone density in the supplemented group compared to the control group (p <0.05), without however, differences in the same group over time (7 and 21 days). The femur there was no difference between control and experimental groups over time, in the metaphyseal region, however, in the diaphyseal region noticed an increase in the number of pixels trabecular in the supplemented group compared to the control group (p = 0.001). It can be concluded that by the structures evaluated in the histomorphometric analysis, supplementation with vitamin D3 had no effect on bone parameters of the jaw and femur, but the radiographic analysis showed an increase in bone density between the control and experimental groups in the jaw to around the implant and femoral diaphysis. / A vitamina D no plasma desempenha um papel chave na regulação do cálcio e homeostase do fosfato com atividades sobre fígado, intestino, rim e osso. Cálcio e o fosfato, obtidos por meio da dieta, são elementos ambientais necessários juntos com a vitamina D para determinar se 1,25-hidroxivitamina D exerce um efeito anabólico ou catabólico sobre o aspecto mineral ósseo. Esta pesquisa foi realizada para avaliar a influência da suplementação de vitamina D3 exerce sobre a densidade óssea do fêmur e mandíbula de camundongos. Foram utilizados camundongos C57BL/6 machos e fêmeas, divididos em dois grupos: 1) grupo controle (n=24) e 2) grupo experimental (n=24) - submetidos à administração sistêmica de vitamina D, por meio de gavagem de vitamina D3 (VitD) na concentração de 10.000 UI por semana. Após 4 semanas da administração da vitamina D foi realizada a cirurgia para colocação de implantes de titânio na região lateral da mandíbula dos animais e foram sacrificados num período de 7 e 21 dias após a colocação do implante. Foram realizadas análises histomorfométrica das regiões de metáfise femoral e mandíbula por meio do programa LAZ v4.2 e radiográfica digital e analisados pelo programa BA-DDX através de radiografia periapical digital, onde foi verificado se houve aumento na densidade óssea entre os grupos analisados através da contagem de pixels de trabeculares. Para a análise estatística foram aplicados os testes Anova e correlação múltipla de Bonferroni e teste de Kruskall Wallis. Os resultados da análise histomorfométrica não mostraram diferenças nas estruturas ósseas (trabéculas e espaços medulares) avaliadas na mandíbula mediante a suplementação de vitamina D3 nos períodos de 7 e 21 dias de cicatrização. Os resultados da análise radiográfica contudo, demonstraram que na mandíbula houve aumento na densidade óssea no grupo suplementado em relação ao grupo controle (p<0,05), não havendo entretanto, diferença no mesmo grupo ao longo do tempo (7 e 21 dias). No fêmur não houve diferença entre grupos controle e experimental ao longo do tempo, na região de metáfise, porém, na região de diáfise notou-se um aumento no número de pixels trabeculares no grupo suplementado em comparação ao grupo controle (p=0,001). Pode-se concluir que pelos pelas estruturas avaliadas na análise histomorfométrica, a suplementação com vitamina D3 não apresentou influência sobre os parâmetros ósseos da mandíbula e do fêmur, porém a análise radiográfica demonstrou um aumento na densidade óssea entre os grupos controle e experimental na mandíbula ao redor do implante e diáfise femoral.

Recentemente demonstramos o desenvolvimento de fibrose na região subendocárdica (SE) do ventrículo esquerdo (VE) em resposta a sobrecarga de volume na fístula aorto-cava (FAC) crônica. A pressão de perfusão coronariana (PPC) associou-se com fibrose SE e com disfunção do VE subsequentes, sugerindo ser o hipofluxo um dos mecanismos envolvidos no remodelamento ventricular.O remodelamento agudo do VE após FAC ainda é desconhecido. O objetivo deste estudo foi investigar a perfusão e o remodelamento cardíaco nas fases agudas após FAC e as possíveis implicações resultantes sobre a função do VE. Ratos Wistar foram submetidos a cirurgia fictícia (sham) ou a FAC e examinados em 3 períodos de seguimento: 1, 3 e 7 dias. Medidas hemodinâmicas sistêmicas e do VE foram realizadas para calcular a PPC e determinar a função do VE. Cortes teciduais do coração foram submetidos à coloração com HE e Sirius red. A necrose de miócitos, o infiltrado leucocitário e a fração de volume de colágeno foram determinados. O fluxo miocárdico, estimado por microesferas coloridas, a atividade de mieloperoxidase (MPO), a expressão de citocinas e a atividade de metaloproteinase-2 (MMP-2) foram determinados ao final de cada seguimento, todos examinados em duas regiões distintas do VE: SE e não SE. Comparados a sham, os grupos FAC apresentaram (média ± desvio-padrão, P <0,05) menores pressões sistêmicas no dia 1 (PAS: 116±6 vs. 88±17; PAD: 84±13 vs. 51±19 mm Hg/s), no dia 3 (PAS: 121±4 vs. 83±28; PAD: 92±5 vs. 46±21 mm Hg/s) e no dia 7 (PAS: 122±6 vs. 96±21; PAD: 93±6 vs. 66±21 mm Hg/s); maior pressão diastólica final do VE no dia 1 (7±3 vs. 15±6 mm Hg/s), no dia 3 (7±3 vs. 18±3 mm Hg/s) e no dia 7 (7±3 vs. 18±5 mmHg/s); menor PPC no dia 1 (77±14 vs. 37±18 mmHg/s), no dia 3 (86±5 vs. 29±20 mmHg/s) e no dia 7 (86±6 vs. 48±19 mmHg/s). Menor função sistólica e diastólica do VE no dia 1 (+dP/dt: 7898±4045 vs. 5828±2262; -dP/dt:. 6626±1717 vs 4728±863 mmHg/s) e no dia 7 (+dP/dt: 7924±2317 vs. 4564±2044; -dP/dt: 6435±1302 vs. 4750±1442 mmHg/s). Houve maior necrose de miócitos no dia 1 no SE (114±5 vs. 208±8) e no não SE (27±3 vs. 42±10) e no dia 3 no SE (82±12 vs. 148±31) e no não SE (21±3 vs. 31±6); maior infiltrado leucocitário no dia 1 no SE (48±5 vs. 84±13) e no não SE (33±4 vs. 40±6), no dia 3 no SE (48±10 vs. 117±13) e no não SE (41±6 vs. 65±8) e no dia 7 no SE (33±5 vs. 50±6) e no não SE (27±6 vs. 38±7); maior fibroplasia no dia 3 no SE (11± 2,6 vs 26±10) e no dia 7 no SE (11±2,3 vs 47±11); maior fibrose no dia 1 no não SE (1,2±0,2 vs. 1,7±0,5), no dia 3 no SE (1,7±0,3 vs. 5,4±0,1) e no não SE (1,4±0,3 vs. 1,8±0,3) e no dia 7 no SE (1,8±0,4 vs. 10,3±2,3) e no não SE (1,7±0,1 vs. 2,8±0,7). O fluxo miocárdico total no dia 7 foi menor, mais intensamente no SE do que no não SE (6.7±1.2 vs. 2.7±1.6 e 7.5±1.3 vs. 4.8±2.6 mL/min/g). Houve maiores níveis de IL-1 no SE e não SE no dia 1 (1050±145 vs. 4225±792 e 1070±138 vs. 4084±359 pg/mg); de TNF- no SE no dia 3 (1415±447 vs. 2037±200 e 1387±279 vs. 1412±301 pg/mg) e IL-6 no SE no dia 7 (3499±397 vs. 4955±429 e 3653±331 vs. 4297±743 pg/mg). No grupo FAC, os animais com PPC <60 mmHg comparados àqueles com PPC >60 mmHg apresentaram maior atividade de MMP-2 no SE e no não SE no dia 1 (69.1±7 e 66.1±7.0 vs. 13.2±4.0 e 11.2±3.4 %), no SE no dia 3 (104.7±39.5 e 22.3±9.0 vs. 26.3±11.3 e 11.5±2.7 %) e no SE do dia 7 (60.5±12.7 e 48.7±4.2 vs. 29.2±8.0 e 6.7±5.8 %). A PPC apresentou correlação direta e significativa com o fluxo do SE (R=0,65), e com o fluxo do não SE (R= 0,62). O fluxo do SE, porém não o do não SE, apresentou correlação direta e significativa tanto com a +dP/dt (R=0,62) quanto com a dP/dt (R=0,67). A PPC apresentou correlação inversa e significativa com a MMP-2 no dia 1 (R=0,86), no dia 3 (R=0,88) e no dia 7 (R=0,93). O remodelamento cardíaco após FAC aguda caracteriza-se por dano isquêmico no SE, resultante da queda da perfusão e implica em disfunção precoce do VE. / Recently, we have demonstrated that fibrosis develops within the subendocardial region (SE) of the left ventricle (LV) in response to chronic volume overload following aortocaval fistula (ACF). Initially low coronary driving pressure (CDP) was associated with subsequent SE fibrosis and LV dysfunction, suggesting that prior low myocardial perfusion may be one of the mechanisms involved in LV remodeling. This study aimed at investigating the role of myocardial blood flow (MBF) in the development of LV remodeling, particularly within SE, during the acute phases of ACF. Wistar rats were submitted to sham (SH) or ACF operations and examined after 1, 3, and 7 days. Apart from haemodynamics, histology (HE- and Sirius red-stained tissue sections), microsphere MBF, and biochemical studies were undertaken in two different LV myocardial regions: SE and non-SE. Compared with SH, ACF showed (mean±S.D.) lower systemic and higher LV end-diastolic pressures resulting in lower CDP at days 1 (77±14 vs. 37±18 mmHg/s), 3 (86±5 vs. 29±20 mmHg/s), and 7 (86±6 vs. 48±19 mmHg/s) with lower systolic and diastolic LV function at days 1 (+dP/dt: 7898±4045 vs. 5828±2262; -dP/dt:. 6626±1717 vs 4728±863 mmHg/s), and 7 (+dP/dt: 7924±2317 vs. 4564±2044; -dP/dt: 6435±1302 vs. 4750±1442 mmHg/s). There was a higher number of myocyte necrotic cells (cells/mm2) within SE (114±5 vs. 208±8) and non-SE (27±3 vs. 42±10) at day 1, and within SE (82±12 vs. 148±31) and non-SE (21±3 vs. 31±6) at day 3; a higher number of leukocyte cells within SE (48±5 vs. 84±13) and non-SE (33±4 vs. 40±6) at day 1, within SE (48±10 vs. 117±13) and non-SE (41±6 vs. 65±8) at day 3, and within SE (33±5 vs. 50±6) and non-SE (27±6 vs. 38±7) at day 7; a greater fibroplasia within SE (11± 2,6 vs 26±10) at day 3, and within SE (11±2,3 vs 47±11) at day 7; a greater fibrosis deposition within SE (1,7±0,3 vs. 5,4±0,1%) and non-SE (1,4±0,3 vs. 1,8±0,3%) at day 3, and within SE (1,8±0,4 vs. 10,3±2,3%) and non-SE (1,7±0,1 vs. 2,8±0,7%) at day 7. Compared with controls, ACF showed increased IL-1 levels within SE and non-SE at day 1 (1050±145 vs. 4225±792 and 1070±138 vs. 4084±359 pg/mg); increased TNF- levels within SE at day 3 (1415±447 vs. 2037±200 pg/mg); increased IL-6 levels within SE at day 7 (3499±397 vs. 4955±429 pg/mg). Compared with ACF rats with CDP >60 mmHg, MMP-2 activity was increased in rats with CDP 60 mmHg within SE and non-SE at day 1 (13.2±4.0 vs. 69.1±7.6 and 11.2±3.4 vs. 66.1±7.0%), and within SE at day 3 (26.3±11.3 vs. 104.7±39.5 and 11.5±2.7 vs. 22.3±9.0%l). At day 7, MBF was more pronouncedly reduced within SE than within non-SE (6.7±1.2 vs. 2.7±1.6 and 7.5±1.3 vs. 4.8±2.6 mL/min/g). CDP was positively and significantly related to MBF in both SE (R=0.65) and non-SE (R= 0.62). MBF within SE was directly and significantly related to both +dP/dt (R= 0,61) and dP/dt (R=0,67). CDP showed negative and significant correlations with SE MMP-2 at days 1 (R=0.86), 3 (R=0.88), and 7 (R=0.93). LV remodeling during the acute phases of ACF occurs within the SE predominantly, results from low perfusion pressure, and contributes to early LV dysfunction.

Coronary atherosclerosis is by far the most frequent cause of ischemic heart disease. Intravascular ultrasound (IVUS) along with virtual histology (VH) is a useful tool for quantification of coronary plaque buildup and provides new insights into the diagnosis of coronary disease. Rupture of vulnerable plaque causing acute coronary syndromes, coronary remodeling maintaining lumen size and plaque phenotype revealing pathological severity are among the most important topics related to atherosclerosis. In this thesis, variations of IVUS-VH-derived thin-cap fibroatheroma (TCFA) definitions are proposed to evaluate the plaque rupture, which is further analyzed in a layered manner; statins effects on coronary remodeling are comprehensively assessed with the implementation of automated IVUS segmentation and registration of IVUS pullbacks based on baseline and 1-year followup datasets; plaque phenotypes are determined and analyzed morphologically and compositionally on segmental basis using the same serial datasets. In addition, our research involves another important coronary disease — coronary allograft vasculopathy (CAV) which is a frequent complication of heart transplantation (HTx). Another intra-coronary imaging modality — intravascular optical coherence tomography (IVOCT) for quantifying CAV is involved. We present an optimal and automated 3-D graph search approach for the simultaneous IVOCT multi-layer segmentation by transforming the 3-D segmentation problem into finding a minimum-cost closed set in a weighted graph. Furthermore, a computer-aided just-enough-interaction refinement method is proposed to help achieve fully satisfactory 3-D segmentation of IVOCT images. We believe this is the first work that provides a fast, efficient and accurate solution for IVOCT multi-layer assessment in the context of CAV. The major contributions of this thesis are: (1) Proving that IVUS-VH-derived TCFA prevalence may be overestimated, and elucidating the potential loss of plaque material during rupture, (2) providing a comprehensive understanding of remodeling in the context of both changing the remodeling direction and changing the remodeling extent, and demonstrating the statin therapy effects on remodeling across patients, based on automated segmentation of IVUS images and registration of serial data, (3) showing that the pathological intimal thickening is the most active plaque phenotype in terms of plaque composition changes and plaque vulnerability progression, and (4) developing and validating a method for multi-layer 3-D segmentation of IVOCT images within a novel interactive environment.

Baroreflex sensitivity (BRS) is often reduced in elderly populations and patients with chronic cardiovascular diseases leading to a concomitant rise in blood pressure variability (BPV) that is associated with increased cardiovascular related morbidity and mortality. Thus, there is a need to better understand the mechanisms by which BPV causes cardiovascular end-organ damage. Animal studies using sinoaortic denervation (SAD) to increase BPV have demonstrated pathologic changes in the structure of the heart and blood vessels; however, there is a paucity of data investigating changes in functional measures of the heart and smaller, resistance type arteries. Furthermore, the pathogenic mechanisms involved in BPV-induced cardiovascular end-organ damage remain unknown. Baroreceptor denervation results in multiple cardiac stressors, many of which are associated with production of reactive oxygen species. Oxidative stress is known to promote cardiovascular end-organ damage but it is unclear if it plays a role in models of increased BPV. Thus, this study was designed to investigate the functional responses of smaller resistance type arteries and the heart to chronic exposure to enhanced BPV. In addition, the role of oxidative stress on these functional responses in a normotensive rat model of increased BPV was also investigated. Rats were subjected to either SAD surgery or a sham procedure and were observed for six weeks. To determine the role of oxidative stress, SAD rats were either treated with the superoxide dismutase mimetic tempol or left untreated. During the observation period, mean blood pressure remained normotensive, whereas baroreflex sensitivity was reduced and BPV increased two to three fold. Weekly in vivo assessment of vascular function of the long posterior ciliary artery (LPCA) demonstrated a significant reduction in endothelial-dependent dilation starting three weeks after SAD surgery compared to the sham group. Endothelial-independent dilation was not affected by SAD. Structural changes were not evident in the LPCA following SAD. However, structural (wall thickness, wall area, and wall area/lumen area ratio) and functional (strain and distensibility) changes were observed in the aorta. Cardiac structural (hypertrophy) and functional (diastolic dysfunction) effects were also evident following six weeks of increased BPV. Antioxidant treatment with tempol did not have any effect on the SAD-induced increase in BPV or decrease in BRS. Nevertheless, chronic tempol treatment prevented or reduced the cardiovascular end-organ damage (endothelial-dependent vascular dysfunction, decreased aortic distensibility, cardiac and vascular hypertrophy, and cardiac dysfunction) observed in the untreated SAD group. These findings suggest that the pathology observed following SAD is at least partly mediated by oxidative stress. Antioxidant treatment in patients with increased BPV (e.g., hypertension, diabetes, heart failure) may prevent or ameliorate cardiovascular end-organ damage and reduce the overall risk for cardiovascular disease events.

Epithelial-mesenchymal transition (EMT) regulates the cellular processes of migration, growth, and proliferation - as well as the collective cellular process of tissue remodeling - in response to mechanical and chemical stimuli in the cellular microenvironment. Cells of the epithelium form cell-cell junctions with adjacent cells to function as a barrier between the body and its environment. By distributing localized stress throughout the tissue, this mechanical coupling between cells maintains tensional homeostasis in epithelial tissue structures and provides positional information for regulating cellular processes. Whereas in vitro and in vivo models fail to capture the complex interconnectedness of EMT-associated signaling networks, previous computational models have succinctly reproduced components of the EMT program. In this work, we have developed a computational framework to evaluate the mechanochemical signaling dynamics of EMT at the molecular, cellular, and tissue scale. First, we established a model of cell-matrix and cell-cell feedback for predicting mechanical force distributions within an epithelial monolayer. These findings suggest that tensional homeostasis is the result of cytoskeletal stress distribution across cell-cell junctions, which organizes otherwise migratory cells into a stable epithelial monolayer. However, differences in phenotype-specific cell characteristics led to discrepancies in the experimental and computational observations. To better understand the role of mechanical cell-cell feedback in regulating EMT-dependent cellular processes, we introduce an EMT gene regulatory network of key epithelial and mesenchymal markers, E-cadherin and N-cadherin, coupled to a mechanically-sensitive intracellular signaling cascade. Together these signaling networks integrate mechanical cell-cell feedback with EMT-associated gene regulation. Using this approach, we demonstrate that the phenotype-specific properties collectively account for discrepancies in the computational and experimental observations. Additionally, mechanical cell-cell feedback suppresses the EMT program, which is reflected in the gene expression of the heterogeneous cell population. Together, these findings advance our understanding of the complex interplay in cell-cell and cell-matrix feedback during EMT of both normal physiological processes as well as disease progression.

Many physiological and pathological processes, such as wound healing and tissue remodeling, are heavily influenced by continuous mechanical cell-cell and cell-ECM communication. Abnormalities that may compromise the biomechanical communication between the cells and the ECM can have significant repercussions on these physiological and pathological processes. The state of the mechanical environment and the reciprocal communication of mechanical signals between the ECM and the cell during wound healing and aged dermal tissue regeneration may be key in controlling the quality of the structure and physical properties of regenerated tissue. This dissertation encompasses a series of studies developed for characterizing the effects of mechanical cues on altering and controlling tissue remodeling, and regeneration in the context of controlling scar formation during wound healing, and the maintenance and regeneration of the dermal extracellular matrix (ECM) during aging. In order to achieve this goal, in vitro models that contained some features of the provisional ECM, and the ECM of the dermis were developed and subjected to an array of quantifiable mechanical cues. Wound models were studied with different mechanical boundary conditions, and found to exhibit differences in initial short-term structural remodeling that lead to significant differences in the long-term synthesis of collagen after four weeks in culture. Dermal models seeded with fibroblasts from individuals of different ages were treated with a hyaluronic acid (HA)-based dermal filler. Changes in the mechanical environment of the dermal models caused by swelling of the hydrophilc HA, resulted in changes in the expression of mechanosensitive, and ECM remodeling genes, essential for the maintenance and regeneration of dermal tissue. Taken together, these data provide new insights on the role of mechanical signals in directing tissue remodeling.