Orientador: Heitor Moreno Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T00:33:13Z (GMT). No. of bitstreams: 1 Girioli_SamiraUbaid_D.pdf: 2811337 bytes, checksum: bc9374b0216cba3ee57f1b107392c0e0 (MD5) Previous issue date: 2009 / Resumo: Segundo o VII JNC e V Diretrizes Brasileiras de Hipertensão Arterial, a hipertensão arterial resistente (HAR) é definida como sendo a elevação persistente dos níveis pressóricos (= 140/90 mmHg) a despeito de tratamento farmacológico tríplice, pleno, incluindo diuréticos, em pacientes com boa adesão e sem causas secundárias de hipertensão arterial ou pseudo-hipertensão. O excesso ou escape de aldosterona pode ocorrer após tratamento crônico com IECA, BRA ou diuréticos tiazídicos, comumente utilizados nestes pacientes ou por hiperaldosteronismo primário não diagnosticado. A espironolactona tem sido apontada como fármaco indispensável no tratamento de HAR por melhorar os níveis pressóricos, mas pouco se sabe sobre a pressão arterial (PA), função endotelial e remodelamento cardiovascular avaliados simultaneamente após sua utilização. O objetivo deste estudo foi avaliar a pressão arterial, a função endotelial, o remodelamento cardiovascular e a função diastólica em hipertensos refratários antes e após a utilização de antagonista de aldosterona, espironolactona, em associação ao tratamento anti-hipertensivo otimizado e individualizado em centro de referência em HAR por 6 meses. Após triagem e adesão rigorosa, 71 pacientes encaminhados ao nosso serviço como hipertensos resistentes foram seqüencialmente incluídos no estudo, após avaliação e caracterização como hipertensos resistentes (HAR, n=39) ou hipertensos controlados (HAC, n=32). O grupo controle foi constituído por pacientes normotensos (CONT, n=37). Anti-hipertensivos eram fornecidos integralmente. Ecocardiograma, Teste de vasodilatação mediada pelo fluxo (VMF), espessura íntima-média de carótidas (IMT), dosagens bioquímicas de concentrações de renina e aldosterona plasmáticas, sódio e potássio séricos e urinários foram realizados na fase inicial (pré-espiro), seguida por associação de espironolactona 25mg/dia ao tratamento anti-hipertensivo por 6 meses (apenas para os grupos HAR e HAC) . Subsequentemente, estes parâmetros foram reavaliados (fase pós-espiro). Após 6 meses de espironolactona, os grupos HAR e HAC apresentaram redução da PA (p<0,001 para PAS e PAD). O grupo HAR apresentou melhora da função endotelial dependente (p<0,001) e independente do endotélio (p=0,007). Os grupos HAR e HAC apresentaram melhora da hipertrofia ventricular esquerda p<0,001) e melhora da função diastólica (índice Kappa HAR: 0,219 e índice Kappa HAC: 0,392) em 7,69% e 15,62%, respectivamente. Os grupos HAR e HAC apresentaram elevação da aldosterona plasmática (p<0,05). A otimização do tratamento da HAR com a associação de espironolactona em pequenas doses, reduz PA, melhora função endotelial, melhora hipertrofia ventricular esquerda e função diastólica a despeito da presença de excesso ou "escape" de aldosterona. / Abstract: According to JOINT VII and V Brazilian Guidelines of Hypertension, resistant hypertension (RH) is defined, as a persistent elevation of blood pressure (= 140/90 mmHg) despite the use of a triple drug regimen at maximal doses including a diuretic, in patients with good compliance and without secondary causes of hypertension or pseudo-hypertension. Aldosterone excess or "escape" can occur after chronic treatment with ACEI, ARB or thiazide-type diuretics, commonly used by these patients or in undiagnosed primary aldosteronism. Spironolactone is thought to be an essential drug in RH treatment because it improves blood pressure, but there are few available data about blood pressure, endothelial function and cardiovascular remodeling evaluated simultaneously with its use. The aim of this study was to assess blood pressure, endothelial function, cardiovascular remodeling and diastolic function in resistant hypertensive patients before and after the use of an aldosterone antagonist, spironolactone, for a six-month period in association with individualized and optimized antihypertensive treatment in a RH reference clinic. After confirming compliance to treatment, 71 hypertensive patients attending our service were included in the study as resistant hypertensive (RH, n = 39) or controlled hypertensive (CH, n = 32) patients. The control group was formed of normotensive patients (CONT, n = 37). All antihypertensive drugs were supplied. Echocardiography, flow-mediated vasodilation, carotid intima-media wall thickness, plasma renin and aldosterone concentrations, plasma and urinary sodium and potassium concentrations were measured at baseline (pre-spironolactone phase), followed by an association of 25 mg/d spironolactone with existing antihypertensive drugs for 6 months (only to RH and CH groups). Subsequently these parameters were reassessed (post-spironolactone phase). After 6 months of spironolactone, the RH and CH groups presented with a reduction in blood pressure (p<0.001 for both systolic and diastolic blood pressures). The RH group had improved endothelial function, both endothelium-dependent (p<0.001) and independent (p = 0.007). RH and CH groups presented with improved left ventricular hypertrophy (p<0.001) and diastolic function (Kappa index RH: 0.219 and Kappa index CH: 0.392) in 7.69% and 15.62%, respectively. There were increases in aldosterone concentrations for RH and CH groups (p< 0.05). Optimized RH treatment with low doses of spironolactone reduces blood pressure and improves endothelial function, left ventricular hypertrophy and diastolic function despite of aldosterone excess or "escape". / Doutorado / Doutor em Farmacologia

Cardiovascular diseases are the major causes of death worldwide. Studying factors leading to initiation and progression of atherosclerosis and its complications leads to a better understanding of underlying mechanisms of this disease and to development of novel treatments. Adhesion of monocytes on the endothelial surface is the initial step of atherosclerosis. The main aim of this study was to establish and test an in vitro model of monocyte adhesion on the endothelial cells and to evaluate the results by means of two methods - measuring the fluorescence signal intensity and counting adhered cells. Because of its well known effects on endothelial cells activation and adhesion molecules expression TNF-α was chosen for endothelial cells stimulation. The lowest concentration of TNF-α affecting the percentage of adhered monocytes in comparision with negative control was 1 ng TNF-α/ml. The optimal concentration of TNF-α increasing the percentage of adhered monocytes was 10 ng TNF-α/ml. The influence of TNF-α on the adhesion was observed already after 5 minutes of coincubation of THP-1 monocytes with HUVEC. Using the optimal concentration of 10 ng/ml led to the highest percentage of adhered monocytes after 30 - 40 minutes of coincubation with HUVEC. Other factor affecting the percentage of adhered...

Lipoprotein binding and metabolism in actively-dividing (subconfluent) and quiescent (postconfluent) bovine aortic endothelial cells (ECs) were qualitatively investigated by fluorescence microscopy using dioctadecylindocarbocyanine-labelled lipoproteins and by indirect immunofluorescence microscopy. LDL and acetylated-LDL (AcLDL) were seen bound to the surfaces of subconfluent ECs (at 4°C or at 37°C), as a random distribution of punctate foci. ECs therefore closely resembled fibroblasts in the distribution of LDL receptors on their surfaces. No binding of LDL was seen on postconfluent EC surfaces by either direct or indirect fluorescence microscopy. The patterns of AcLDL binding on postconfluent ECs resembled those on subconfluent ECs. Intracellular LDL and AcLDL occurred as perinuclear accumulations of large fluorescent disc-shaped profiles in subconfluent ECs. These accumulations were shown to arise from surface-bound material by pulse-chase experiments. Intracellular LDL was absent in the majority of postconfluent ECs, while AcLDL accumulation was massive. "Wounding" of cultures allowed simultaneous assessment of lipoprotein metabolism in quiescent and actively-dividing areas of the same culture. Quantitative assessments of the above-mentioned phenomena were made using ¹²⁵I-labelled lipoproteins. Receptor-mediated binding of LDL decreased five to ten-fold as the cultures modulated from subconfluent to postconfluent morphology. No receptor-bound LDL was detected in postconfluent ECs. Conversely, the amount of AcLDL bound increased at least fivefold during EC growth in parallel cultures. The amounts of lipoproteins endocytosed and metabolised were generally related proportionately to the amounts bound in each case. The distribution of LDL receptors on cultured cells was also investigated at the ultrastructural level using colloidal gold-conjugated LDL as a probe, and similarly labelled antibodies as probes. Whole-mounted cells with receptor probes bound to them were examined directly in the transmission electron microscope. The topographical distribution of LDL receptors has not been investigated by these techniques before. A novel method of preparing cytochemically-labelled, whole-mounted cells from styrene culture dishes was developed and used in this study. LDL Receptors expressed on the surfaces of human skin fibroblasts served to standardise these colloidal gold techniques and fortuitously led to new information on receptor distribution. Normal (FGo) and LDL receptor-negative mutant fibroblasts (GM 2000) acted as positive and negative controls respectively. Normal fibroblast LDL receptors were grouped into clusters consistent in size with coated pits (200 - 500 nm in diameter). A novel finding was the presence of a diffuse population of receptors scattered randomly amongst the clustered receptors. Another mutant fibroblast, GM 2408A, known to have an aberrant LDL receptor distribution, was also examined. Its receptors were shown to be dispersed singly, and in occasional groups of two and three, at random over the cell surfaces. No clusters were detected. The receptor-negative GM 2000 bound virtually no probes. While not as sensitive as the colloidal gold-conjugated LDL probe, an antireceptor monoclonal antibody (IgG-C7), localised by indirect immunogold labelling, gave similar results when applied to the above cells. This was taken as strong corroborative evidence that the LDL receptor distributions as determined by colloidal gold-conjugated LDL were correct. It is suggested that the dispersed population of receptors on normal fibroblasts may represent newly-emerged recycling receptors which have yet to cluster in coated pits. A further new finding reported here is the existence of the same two patterns of LD L receptors, dispersed and clustered, on the surface of subconfluent ECs. It was noted, from the study of whole-mounted and thin-sectioned cells, that the receptors were preferentially arranged in rings following the circumference of coated pit areas on the cell surface. Often these rings associated in groups or even coalesced into compound clusters. The significance of these groupings is not yet understood. In sharp contrast to the situation on subconfluent ECs, no LDL receptors (probed with the extremely sensitive colloidal-gold conjugated LDL) could be detected at the EM level on the surface of postconfluent ECs. Active cells in wounded postconfluent monolayers expressed abundant receptors detected at the EM level. It is concluded that postconfluent quiescent bovine aortic ECs in vitro metabolise virtually no LDL via the LDL-receptor pathway due to a vanishingly low number of LDL receptors. This contrasts with the ability of postconfluent cells to metabolise relatively large amounts of AcLDL via a receptor-mediated mechanism. The significance of these conclusions is discussed with respect to the interaction of plasma lipoproteins with the endothelium in vivo.

N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) has been shown to cause changes in cultured endothelial cells and smooth muscle function at concentrations from 5 to 25 mM. To determine whether HEPES also affects vascular permeability, the effects of two buffers, HEPES and phosphate, were compared in isolated perfused rabbit lungs. Hemodynamic parameters and vascular protein permeability-surface area products (PS) were measured after perfusion with the buffers. Endothelial permeability was measured for an anionic and a cationic albumin to assess the charge effects of the zwitterion buffer. With HEPES, there were no changes in vascular pressure or resistance but permeability was affected. Cationic albumin permeability increased with 12 mM HEPES (8.7(phosphate) → 30(12 mM HEPES) x ml · min-1 · g dry lung-1 x 10-2) as did the anionic albumin PS (2.7(phosphate) → 3.52(12 mM HEPES). The cationic PS returned to baseline (8.1(60 mM HEPES)) at 60 mM HEPES, but the anionic PS did not change from the 12 mM HEPES (4.01(60 mM HEPES)). In summary, we find that HEPES is not innocuous. Although hemodynamic parameters did not change, endothelial permeability was increased when HEPES was used at normal concentrations. Therefore, HEPES should be used with caution as a physiological buffer in perfused organ systems.

Endothelium-derived vasodilators, i.e., nitric oxide (NO), prostacyclin (PGI2) and prostaglandin E2 (PGE2), play important roles in maintaining cardiovascular homeostasis. C-reactive protein (CRP), a biomarker of inflammation and cardiovascular disease, has been shown to inhibit NO-mediated vasodilation. The goal of this study was to determine whether CRP also affects endothelial arachidonic acid (AA)-prostanoid pathways for vasomotor regulation. Porcine coronary arterioles were isolated and pressurized for vasomotor study, as well as for molecular and biochemical analysis. AA elicited endothelium-dependent vasodilation and PGI2 release. PGI2 synthase (PGI2-S) inhibitor trans-2-phenyl cyclopropylamine blocked vasodilation to AA but not to serotonin (endothelium-dependent NO-mediated vasodilator). Intraluminal administration of a pathophysiological level of CRP (7 μg/mL, 60 min) attenuated vasodilations to serotonin and AA but not to nitroprusside, exogenous PGI2, or hydrogen peroxide (endothelium-dependent PGE2 activator). CRP also reduced basal NO production, caused tyrosine nitration of endothelial PGI2-S, and inhibited AA-stimulated PGI2 release from arterioles. Peroxynitrite scavenger urate failed to restore serotonin dilation, but preserved AA-stimulated PGI2 release/dilation and prevented PGI2-S nitration. NO synthase inhibitor L-NAME and superoxide scavenger TEMPOL also protected AA-induced vasodilation. Collectively, our results suggest that CRP stimulates superoxide production and the subsequent formation of peroxynitrite from basal released NO compromises PGI2 synthesis, and thus endothelium-dependent PGI2-mediated dilation, by inhibiting PGI2-S activity through tyrosine nitration. By impairing PGI2-S function, and thus PGI2 release, CRP could promote endothelial dysfunction and participate in the development of coronary artery disease.

The cardiovascular system helps maintain blood pressure and blood flow to the different organ systems through many elaborate mechanisms. These mechanisms include the different blood vessels, each with their own properties, as well as both neural and humoral factors. The vessels that are most relevant here are arterioles, also known as resistance vessels, as they play a significant role in regulating organ blood flow, vascular resistance, and blood pressure in many different physiological conditions, such as exercise. More specifically, the focus of this paper is the endothelial layer of the arteriolar wall and its role in attenuating sympathetic adrenergic vasoconstriction, or sympatholysis. Exercising skeletal muscle cells require an increase in blood flow to adequately meet their oxygen and nutrient demands. In order to accomplish this, there is an increase in cardiac output by the heart and also a redistribution of blood flow away from inactive regions towards active muscle cells. This critical redistribution of blood flow depends on the sympathetic nervous system, which increases in activity during contraction to cause vasoconstriction of the arterioles that supply other inactive organs except the brain. Despite this increase in sympathetic nerve activity, there is also profound vasodilation in the microvasculature of active skeletal muscle cells. It is this paradox that helps match the increase in metabolism with an increase in blood flow during exercise, and it is also this mechanism that has been coined ‘functional sympatholysis.’ Although much effort has been put into studying the mechanism through which functional sympatholysis occurs, the existing data and evidence are not sufficient to deduce a clear picture at this time. There are inconsistencies regarding the functional distribution of alpha-adrenergic receptors, the role of non-adrenergic receptors, the impact of many different metabolic factors, and finally also the contribution of non-metabolic factors. Due to such contrasting data, it is clear that further research will need to be conducted in order to obtain a concrete explanation for sympatholysis. A recent study has postulated that the process of sympatholysis may primarily involve the endothelium. This study used various manipulations that involved endothelium-dependent vasodilatory responses as well as endothelium-independent vasodilatory responses intersected with sympathetic adrenergic nerve activity to determine that only those vasodilatory agents that functioned using the endothelium were able to attenuate sympathetic adrenergic vasoconstriction. This compelling evidence has made way for further inquiry into the endothelium’s role in this very important process. Due to the fact that the greatest amount of research has been devoted to studying the contraction-related attenuated responsiveness of alpha-adrenergic receptors, a hypothetical study and its various methods are proposed in this paper. This hypothesis states that both adenosine triphosphate and flow-mediated dilation, two vasodilatory stimuli that rely on a functional endothelium, are sympatholytic agents, whereas adenosine, which acts on vascular smooth muscle to cause vasodilation, is not sympatholytic. The conclusions that might be drawn from such a study and their various implications are also discussed. Finally, the major relevancy in this topic relates to the fact that sympatholysis or impaired sympatholysis may be a factor in many metabolic and cardiovascular diseases along with exercise. Some of the diseases discussed here are type II diabetes, hypertension, and chronic myocardial infarction. A concrete understanding of the mechanism by which this process occurs would potentially help invent new treatment plans and prevention. At this point, it seems probable that the endothelium does play a significant role in sympatholysis, but whether it is the primary dictator and whether there are also other influences that are absolutely essential still remains relatively uncertain.

To determine differences in A1- and A2-selective adenosine effects on coronary endothelium, isolated rabbit hearts (n = 18) were perfused with erythrocyte-enriched buffer at constant left ventricular volume and physiologic flow rates. After 10-20 minutes of stabilization, the perfusate was changed to contain an A1-selective agonist (N6-cyclopentyladenosine, CPA; high dose, 4.26 X 10-7M or low dose, 10-8M), or an A2-selective agonist ((5'-(N-cyclopropyl) carboxaminoadenosine, CPCA; high dose, 4.45 X 10-6M or low dose 10-7 M). Before and during each treatment period of 1-15 minutes aortic and left ventricular pressures and rates of change were recorded. Hearts were then perfused intravascularly with ruthenium red stain (RR) dissolved in filtered 2.5% glutaraldehyde, and processed by routine electron microscopic methods for ultrastructural examination. Of the hemodynamic parameters measured only aortic pressure increased with CPA, and decreased with CPCA, indicating the expected pharmacologic efficacy at the doses used. However, no observable differences in RR uptake was noted between hearts that received no adenosine agonist and either low- or high-dose CPA. CPCA-treated hearts had noticeable RR uptake into endothelium with both low and high dose levels, with a marked uptake in hearts receiving high doses of this A2 agonist. These results provide direct morphological evidence that supports the concept that endothelial macromolecular uptake is an adenosine A2-mediated process.

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Human endothelium is capable of expressing a variety of molecules, including cytokines and growth factors, critical to inflammation. This aspect of coronary endothelium has not been studied in detail. In this study, we report, for the first time, expression of multifunctional cytokines by human coronary artery endothelial cells (HCAEC) and their regulation by inflammatory cytokines and glucocorticoids. We also compared expression of cytokine transcripts in two additional cell lines derived from pulmonary artery (HPAEC) and umbilical vein (HUVEC) endothelium. HCAEC expressed transcripts for interleukin 5 (IL-5), IL-6, IL-8, and monocyte chemotactic protein-1 (MCP-1) constitutively. Induction of IL-1α, IL-6, granulocyte- macrophage colony-stimulating factor (GM-CSF), and MCP-1 was seen following treatment with TNFα. We found no expression of IL-1RA, IL-2, IL-4, IL-13, TNF-α, or IFN-γ in HCAEC. IL-1β and TNF-α synergistically induced IL-6 and GM-CSF and additively induced IL-8 and MCP-1 production, while IL-2, IL- 10, IFN-α, and IFN-γ had little or no additional effects. Interestingly, no IL-1α or IL-5 protein product was found even after maximal stimulation of HCAEC. No significant differences were seen in the profile of cytokine genes expressed by HCAEC, HPAEC, or HUVEC. Glucocorticoids inhibited IL-8 production from all three cell lines. This study demonstrates that human coronary endothelial cells are capable of expressing a wide variety of multifunctional cytokines which may be of relevance to vascular inflammation.