Orientador: Heitor Moreno Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T19:23:52Z (GMT). No. of bitstreams: 1 Figueiredo_ValeriaNasser_D.pdf: 1480024 bytes, checksum: 990076c988ddb59b0ca20faed103fff3 (MD5) Previous issue date: 2012 / Resumo: A definição de hipertensão arterial resistente (HAR) inclui pacientes cuja pressão arterial (PA) permanece acima da meta apesar do uso de 3 classes de anti-hipertensivos bem como aqueles que usam 4 ou mais classes e possuem pressão controlada, excluída a pseudo-resistência. A hiperatividade do sistema nervoso simpático está criticamente envolvida na patogênese da hipertensão arterial, correlacionando-se positivamente com a gravidade da hipertensão arterial e maior variabilidade da frequencia cardíaca, estando ainda envolvida no efeito do avental branco (EAB). Ademais, os distúrbios do sono frequentemente associam-se à HAR. Objetivos: Avaliar se a presença do EAB associa-se a maior proporção (adicional) de lesões de órgão alvo em HAR; avaliar se a disfunção do sistema nervoso autônomo, quantificada através da variabilidade da frequência cardíaca, correlaciona-se com diferentes níveis de PA nestes pacientes e verificar se o risco para apneia obstrutiva do sono e qualidade do mesmo está associado ao EAB. Casuística e Métodos: subestudo 1 - Foram incluídos 121 pacientes diagnosticados como hipertensos resistentes em seguimento no ambulatório de Hipertensão Resistente do HC-FCM/UNICAMP e divididos em 2 grupos: HAR+EAB (n=66) e HAR-EAB (n=61). Foram realizados estudos para investigação do remodelamento cardiovascular (Ecocardiografia), da função renal (microalbuminúria e Clearance de creatinina); subestudo 2 - foram incluídos 44 pacientes diagnosticados como hipertensos resistentes em seguimento no ambulatório de Hipertensão Resistente do HC-FCM/UNICAMP e divididos em 2 grupos: HAR+EAB (n=25) e HAR-EAB (n=19). Foram realizados estudos para investigação da avaliação da variabilidade da frequência cardíaca (sistema não invasivo - Holter 24 horas), bem como responderam ao Questionário índice de qualidade do sono de Pittsburgh e Questionário de Berlim (avaliação do risco para apneia obstrutiva do sono). Resultados: subestudo 1- os dois subgrupos eram semelhantes em distribuição de gênero, idade e índice de massa corporal. Os valores de PA observados foram: consultório= 169,8±15,8/95,1±14,0 (HAR+EAB) e 161,9±9,0/90,1±10,4 mmHg (HAR-EAB) e MAPA= 143,0±12,8/86,1±9,9 (HAR+EAB) e 146,1±13,6/85,1±14,9 mmHg (HAR-EAB). Não houve diferença significativa entre os 2 subgrupos quanto ao IMVE (HAR+EAB= 132±38; HAR-EAB= 125±32 g/m²), clearance de creatinina (HAR+EAB= 78±38; HAR-EAB= 80±28 ml/min/m²) e microalbuminúria (HAR+EAB= 44±68; HAR-EAB= 49±53 mg/g Cr); subestudo 2 - os dois subgrupos eram semelhantes em distribuição de gênero, idade e índice de massa corporal. A despeito da alta prevalência de risco para apneia obstrutiva do sono e qualidade de sono ruim ter sido observada em ambos os subgrupos, o subgrupo HAR+EAB apresentou atividade simpática aumentada durante o período noturno (HAR+EAB=58,9±20,9 e HAR-EAB=39,8±22,9, p<0,05). Conclusão: subestudo 1 - demonstramos que nesta amostra de pacientes com HAR, o EAB não se associou a maior proporção de lesões em órgãos alvo (quando avaliados rins e coração); subestudo 2 - a hiperativação simpática durante o período de sono ocorreu somente em hipertensos resistentes com EAB, apesar da influência semelhante de distúrbios do sono e da qualidade do mesmo em ambos os grupos / Abstract: Background: The revised definition of resistant hypertension (RHTN) includes both patients whose blood pressure (BP) is uncontrolled on three or more medications and those whose BP is controlled when using four or more antihypertensive medications. White coat effect (WCE) originates from an alerting reaction by the patient while being examined in a medical environment and is frequently associated with an increase in heart rate and blood pressure (BP). It is known that high prevalence of obstructive sleep apnea in resistant hypertension (RH) and its subsequently nighttime sympathetic overactivation. Objectives: substudy 1- the relationship between occurrence of WCE and target organ damage (TOD) has not yet been assessed in true RHTN; substudy 2 - the aim of the study was to investigate the influence of the pattern of autonomic activity in the circadian rhythm in true resistant hypertension with and without WCE and its relationship with quality of sleep and sleep disorders. Methods: substudy 1- one hundred twenty-seven RHTN patients were identified with WCE (WCE) (66) and without WCE (non-WCE) (61).All patients were submitted to office BP measurement, ABPM, echocardiography and renal function evaluation; substudy 2 - consecutive stable patients with RHTN (44 in number) were evaluated for the risk of obstructive sleep apnea by the Berlin Questionnaire, sleep quality by the Pittsburgh Sleep Questionnaire Index and were submitted to office BP measurement, ABPM and 24-hour Holter monitoring. Results: substudy 1- Office BP were 169.8 ± 15.8 / 95.1 ± 14.0 (WCE) and 161.9 ± 9.0 / 90.1 ±10.4 mmHg (non-WCE), ABPM = 143.0 ± 12.8 / 86.1 ± 9.9 (WCE) and 146.1 ± 13.6 / 85.1 ± 14.9 mmHg (non-WCE). No statistical differences were observed between WCE and non-WCE subgroups with respect to left ventricular mass index (WCE= 131 ± 4.7; non-WCE= 125 ± 2.9 g/m²), creatinine clearance (WCE = 78 ± 4.7; non-WCE= 80 ± 3.6 ml/min/m²) and microalbuminuria (WCE= 44 ± 8.4; non-WCE= 49 ± 6.8 mg/g Cr); substudy 2 - RHTN patients were identified with WCE (WCE) (25) and without WCE (non-WCE) (19). Office BP was 170.7±17.2/94.8±14.0 (WCE) and 161.7±08.6/90.3±11.4 mmHg (non-WCE), daytime ABPM = 144.0±13.4/77.3±17.3 (WCE) and 146.2±15.6/84.0±15.0 mmHg (non-WCE). Despite of the similar results regarding quality of sleep and risk of OSA in both groups, significant differences were observed between WCE and non-WCE subgroups regarding low frequency in normalized units (LF nu) during night time (WCE=58.9±20.9 and non-WCE 39.8±22.9, p<0.05). Conclusion: substudy 1- this finding may suggest that WCE is not associated with additional increase of TOD in true RHTN subjects; substudy 2 - the sympathetic overactivation during the nighttime prior the medical appointment occurred in RH patients with WCE despite of the influence of sleep disorders / Doutorado / Farmacologia / Doutor em Farmacologia

Considerable evidence supports the claim that a hyperactive sympathetic nervous system (SNS) is involved in most cases of human hypertension, and therefore a more thorough understanding of the central regulation of the SNS may help elucidate novel therapeutic options. The PVN is a key region in SNS regulation of blood pressure (BP) and heart rate (HR). Stimulation of the parvocellular PVN neurons has been shown to enhance sympathetic outflow and thereby increase BP. Brain-derived neurotrophic factor (BDNF), a modulator of neuronal activity is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to several hypertensive stimuli such as stress and hyperosmolarity, and previous studies from our lab demonstrated that both acute injections or chronic overexpression of BDNF in the PVN elevate SNS activity and BP. However, the BDNF-mediated hypertensive mechanisms are not completely understood. PVN neurons are under tonic inhibition from NTS catecholaminergic projections under baseline condition as indicated by significant BP increase after selective lesioning of NTS NE-ergic neurons. In addition, BDNF has been shown to alter NE-ergic signaling in multiple brain regions raising the possibility that BDNF may increase SNS activity and BP by interfering with NE-ergic inhibition of PVN sympathoregulatory neurons. Therefore, we tested the hypothesis that BDNF increases SNS activity and BP in part by disabling inhibitory actions of NTS catecholaminergic projections to the PVN by altering the expression of adrenergic receptors and NET in the PVN. First, blood pressure was recorded using radiotelemetry in male Sprague-Dawley rats following bilateral microinjections of adeno-associated viral vectors expressing green fluorescent protein (GFP) or myc-tagged BDNF in the PVN and microinjections of phosphate saline buffer (PBS) or Anti-Dopaine Beta Hydroxylase (DBH)-conjugated saporin (DSAP), a catecholaminergic neuron-specific neurotoxin, into the NTS. Blood pressure was monitored both during resting conditions and during acute stress tests. A second group of rats received bilateral microinjections of adeno-associated viral vectors expressing GFP or myc-tagged BDNF in the PVN, and were sacrificed after 5 weeks. PVN and NTS samples were then selectively isolated using a brain punch tool, and expression of TH, DBH, 1a, 1b, 2a, 1, 2 receptors, and norepinephrine transporter (NET) was analyzed using quantitative RT-PCR. Our results show that BDNF overexpression in the PVN leads to increased expression of catecholamine synthesizing enzymes in the NTS. In addition, both BDNF overexpression in the PVN, and DSAP lesioning in the NTS increased MAP compared to control rats. However, combined treatment with BDNF and DSAP failed to have any additional hypertensive effects suggesting that BDNF treatment may abolish the inhibitory effect of NTS catecholaminergic projections. Lesioning the NTS catecholaminergic neurons didn’t appear to have a significant effect on mean arterial pressure response to the stress tests, although DSAP treatment appeared to decrease the initial heart rate response to acute stress, and this effect was most pronounced in GFP rats. These results indicate that BDNF overexpression in the PVN desensitizes sympathoregulatory neurons to inhibitory NTS catecholaminergic projections during baseline conditions.

Ischemic injury in the heart is followed by an increase in SNS activity and the higher this activity, the poorer patient outcomes. An index of SNS activity in models of ischemia can be achieved by measuring NE, β-AR, and perhaps indirectly PDE4 to give an intracellular aspect on SNS signaling. A 20 minute ischemia-reperfusion was induced in a rat model with physiological measurements at 2-5 weeks post IR. At 3 weeks post IR, rats displayed increased PDE4 expression, decreased β 1-AR expression, increased plasma NE, decreased tissue NE storage, increased Doppler E/A ratio and unchanged LV ejection fraction. PET analysis with FDG revealed no infarct at 2 weeks, while analysis with [13N]NH3 displayed no resting flow defect but revealed trends in flow reserve impairment as early as 2.5 weeks with recovery at 5 weeks post-surgery. Applications of this model could be non-invasive imaging of PDE4 with (R)-[11C]Rolipram PET at early time points for development towards prognostic and therapy guidance in humans.

INTRODUÇÃO: O consumo moderado de vinho tinto está inversamente associado ao desenvolvimento de doença cardiovascular. Efeitos do vinho tinto no sistema nervoso simpático e na reatividade vascular não estão totalmente esclarecidos. MÉTODOS: Foi avaliada a atividade simpática do nervo muscular e a dilatação mediada pelo fluxo na artéria braquial por ultrassom em 10 indivíduos hipercolesterolêmicos, 9 hipertensos e 7 controles antes e após o consumo de vinho tinto durante 15 dias. Medidas hemodinâmicas foram realizadas com Finometer: pressão arterial sistólica, diastólica, freqüência cardíaca, débito cardíaco e resistência vascular sistêmica foram calculados continuamente durante a microneurografia. Para avaliação da atividade simpática, utilizou-se punção de nervo fibular - esta foi medida como bursts/min durante período basal, teste do gelo e exercício estático com 30% da contração voluntária máxima. RESULTADOS: Após 15 dias de vinho tinto, a atividade simpática aumentou de forma significante em hipertensos e hipercolesterolêmicos (p < 0,05); porém, a dilatação mediada pelo fluxo aumentou somente em hipercolesterolêmicos (p < 0,05). As pressões arteriais sistólica e diastólica não apresentaram mudança significante. Não houve mudança na freqüência cardíaca. Houve aumento do débito cardíaco em controles, diminuição da resistência arterial sistêmica durante o gelo em controles no período basal. CONCLUSÃO: O consumo de vinho tinto aumentou a atividade simpática em hipertensos e hipercolesterolêmicos; porém, somente estes experimentaram melhoria da função endotelial, o que sugere diferentes mecanismos na regulação da função endotelial. / Introduction: Moderate red wine intake is inversely associated with development of cardiovascular disease. Red wine effects in sympathetic activity and vascular reactivity are not fully understood. Methods: Muscle sympathetic nerve activity and flow mediated dilatation of brachial artery by ultrasound were evaluated in 10 hypercholesterolemic, 9 hypertensive, and 7 controls subjects before and after red wine intake during 15 days. Hemodynamic measures were done with Finometer: arterial blood pressure, heart rate, cardiac output, and systemic vascular resistance were assessed during mycroneurography. The sympathetic activity was evaluated during baseline, cold test and isometric exercise. Results: After 15 days of red wine intake, sympathetic activity increased significantly in hypertensives and hypercholesterolemics (p < 0.05). On the other hand, flow mediated dilation increased after red wine only in hypercholesterolemics (p < 0.05). Systolic and diastolic blood pressure as well as heart rate did not change significantly. Cardiac output increased in controls and systemic vascular resistance decreased during cold test in controls. Conclusion: There were similar increases in sympathetic activity in hypertensive and hypercholesterolemic subjects; however, endothelial function was restored only in the latter group, which suggests different mechanisms regulating endothelial function.

Right ventricular function (RV) is one of the most important predictors of prognosis in many cardiovascular disease states. Despite the significance of RV function to survival, there are no therapies that directly nor selectively improve RV function. As well, the basis for RV failure is poorly understood. This is particularly relevant for patients with pulmonary arterial hypertension (PAH), where RV failure in the setting of pressure overload is the leading cause of death. PAH will be introduced in the 2nd chapter of this thesis by comparing and refining contemporary mortality risk assessment strategies. I will then explore 1) RV neurohormonal function and, 2) RV energetics, two molecular pathways thought to be involved in the pathogenesis and progression of maladaptive RV failure. I employed small animal molecular imaging using positron emission tomography (PET) to non-invasively investigate these pathways. The PET imaging techniques employed in this thesis have the unique potential for translation to human studies, to further explore disease mechanisms.

Intravenous injection of substance P (SP) increases blood pressure in normotensive rats by stimulating sympathetic ganglia. This study compared the effects of SP to increase renal nerve firing and blood pressure in normotensive and hypertensive rats treated with chlorisondamine. The increase in renal nerve firing was greatest in spontaneously hypertensive rats (SHR), intermediate in Wistar rats, and least in Wistar-Kyoto (WKY) rats. Blood pressure was increased more in SHR than in Wistar rats. Blood pressure was not increased in WKY rats. Responses to the ganglionic stimulant 1, 1-dimethyl-4-phenylpiperazinium were the same in the three strains. These results suggest that there is a selective increase in the action of SP on sympathetic ganglia of SHR and that ganglion responsiveness to SP is correlated with its effect on blood pressure.

Intravenous injection of substance P (SP) increases renal nerve firing and heart rate in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKYs) by stimulating sympathetic ganglia. Blood pressure is increased in SHRs but lowered in WKYs. This study assesses the role of neurokinin-1 (NK1) receptors in mediating the ganglion actions of SP. Rats for functional studies were anesthetized and then treated with chlorisondamine. Renal nerve, blood pressure, and heart rate responses to intravenous injection of the NK1 receptor agonist GR-73632 were similar but less than those to equimolar doses of SP in SHRs. GR-73632 only slightly increased renal nerve firing and heart rate and lowered blood pressure in WKYs. The NK1 receptor antagonist GR-82334 (200 nmol/kg iv) blocked the ganglionic actions of GR-73632 and the pressor response to SP in SHRs. It reduced the renal nerve and heart rate responses by 52 and 35%. This suggests that the pressor response to SP is mediated by ganglionic NK1 receptors and that NK1 receptors also have a prominent role in mediating the renal nerve and heart rate responses to SP. Quantitative autoradiography showed that NK1 receptors are more abundant in the superior cervical ganglia of SHRs. RT-PCR showed increased abundance of NK1 receptor mRNA in SHRs as well. These observations suggest that the greater ganglionic stimulation caused by SP in SHRs is due to upregulation of NK1 receptors.

The two recently isolated hypothalamic peptides orexin A and orexin B, also known as hypocretin 1 and 2, are reported to be important signaling molecules in feeding and sleep/wakefulness. Orexin-containing neurons in the lateral hypothalamus project to numerous areas of the rat brain and spinal cord including the intermediolateral cell column (IML) of the thoracolumbar spinal cord. An in vivo and in vitro study was undertaken to evaluate the hypothesis that orexins, acting on sympathetic preganglionic neurons (SPNs) in the rat spinal cord, increase sympathetic outflow. First, orexin A (0.3, 1, and 10 nmol) by intrathecal injection increased mean arterial pressure (MAP) and heart rate (HR) by an average of 5, 18, and 30 mmHg and 10, 42, and 85 beats/min in urethane-anesthetized rats. Intrathecal injection of saline had no significant effects. Orexin B (3 nmol) by intrathecal administration increased MAP and HR by an average of 11 mmHg and 40 beats/min. The pressor effects of orexin A were attenuated by prior intrathecal. injection of orexin A antibodies (1:500 dilution) but not by normal serum albumin. Intravenous administration of the α1-adrenergic receptor antagonist prazosin (0.5 mg/kg) or the β-adrenergic receptor antagonist propranolol (0.5 mg/kg) markedly diminished, respectively, the orexin A-induced increase of MAP and HR. Second, whole cell patch recordings were made from antidromically identified SPNs of spinal cord slices from 12- to 16-day-old rats. Superfusion of orexin A or orexin B (100 or 300 nM) excited 12 of 17 SPNs, as evidenced by a membrane depolarization and/or increase of neuronal discharges. Orexin A- or B-induced depolarizations persisted in TTX (0.5 μM)-containing Krebs solution, indicating that the peptide acted directly on SPNs. Results from our in vivo and in vitro studies together with the previous observation of the presence of orexin A-immunoreactive fibers in the IML suggest that orexins, when released within the IML, augment sympathetic outflow by acting directly on SPNs.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19785号 / 農博第2181号 / 新制||農||1042(附属図書館) / 学位論文||H28||N5001(農学部図書室) / 32821 / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 河田 照雄, 教授 金本 龍平, 教授 谷 史人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Hypertension is a major public health issue impacting one in two adults in the United States and accounts for 10 million deaths each year worldwide. It is a leading risk factor for multiple diseases, including stroke, myocardial infarction, chronic kidney disease, and peripheral artery disease. The prevalence of hypertension increases with age in both sexes. In addition, aging is associated with significantly higher hypertension-related morbidity and mortality and insufficient control of high blood pressure. Critically, menopause is linked to a 2-fold increase in hypertension risk and premenopausal women have lower hypertension rates compared to men of similar age. Increased sympathetic nervous system activity, inflammation, and remodeling of large arteries like the aorta have been implicated in both normal aging and the pathophysiology of hypertension. Despite extensive hypertension research and the rapidly growing aging population, only 4% of hypertension studies focus on aging. Increased molecular insight into the mechanisms mediating arterial remodeling in age-dependent hypertension could uncover potential therapeutics for more targeted treatment of hypertension. In this thesis, Sprague Dawley rats were used in the models of normal aging and norepinephrine-induced hypertension to investigate the complex interplay between aging, sympathetic nervous system activity, and inflammation in arterial remodeling in age-dependent hypertension and potential sex differences. Our key findings from the abdominal aorta and renal artery are (1) Sex-dependent changes in the phosphorylation of c-Src kinase and ERK1/2, and expression of caveolin-1, (2) Altered expression of alpha-SMA and MHY-11, (3) Partial recapitulation of aged hypertensive phenotype in the abdominal aorta of young male rats following NE-infusion. Our proteomic and phosphoproteomic analyses of the aorta of young normotensive and aged hypertensive male rats have identified 58 differentially expressed proteins and 39 differentially phosphorylated proteins. Proteome analysis further revealed that the proteins in extracellular matrix, actin cytoskeleton and inflammatory pathways were the top affected proteins or pathways. Moreover, in phosphoproteome analysis, major differences were found in neurons, synapse structures, vascular smooth muscle cells, and focal adhesions. Notably, approximately two-thirds of differentially phosphorylated proteins (22 out of 39) were found to be at neurons and synapses. In the assessment of inflammatory mediators, we found that increases in multiple homeostatic cytokines including, CCL21, MMP2, and osteopontin were associated with the aortic remodeling in age-dependent hypertension. Collectively, these results support a model in which aging, increased sympathetic nervous system activity, and inflammation contribute to arterial remodeling in age-dependent hypertension. / 2024-11-02T00:00:00Z