Abstract Cardiac hypertrophy provides an adaptive mechanism to maintain cardiac output in response to increased workload, and although initially beneficial, hypertrophy eventually leads to heart failure, a major cause of morbidity and mortality in Western countries. The hypertrophic response in cardiac myocytes is accompanied by e.g. activation of signal transduction pathways, such as mitogen-activated protein kinases (MAPKs), and complex changes in gene programming. The purpose of this study was to characterize gene expression patterns in experimental models of cardiac load by using high-throughput DNA microarray technologies. In the present study, changes in gene expression were evaluated in response to acute pressure overload and prolonged hypertension as well as during the development of left ventricular hypertrophy (LVH) and the transition to diastolic heart failure in an animal model of genetic hypertension, the spontaneously hypertensive rat (SHR). Increased expression of several immediate early genes was seen in response to acute hemodynamic overload in vivo. The transition from LVH to diastolic hypertensive heart failure was almost exclusively associated with changes in genes encoding extracellular matrix proteins and their regulatory processes showing the importance of progressive extracellular matrix remodeling. The effect of p38 MAPK activation on gene expression patterns in vivo was elucidated. Cardiac-specific overexpression of p38 MAPK resulted in upregulation of genes controlling cell division and inflammation as well as cell signaling and adhesion. Accordingly, the functional role of p38 MAPK was related to myocardial cell proliferation, inflammation and fibrosis. Finally, temporal analysis of mechanical stretch induced gene expression changes in neonatal rat cardiomyocyte cultures in vitro indicated that mechanical stretch induced complex gene expression profiles, demonstrating that both positive and negative regulators are involved in the hypertrophic process. Many novel stretch responsive genes were identified, and a subset of them may be putative downstream targets of p38 MAPK. In conclusion, in the present study a number of well-established gene expression changes of cardiac hypertrophy were observed and novel modulators associated with increased cardiac load, such as thrombospondin-4, were identified. The study provides a better understanding of molecular mechanisms associated with increased cardiac load, and may indicate potential targets for novel therapeutic interventions.

Diagnosis of diabetes mellitus, presence of hyperglycemia, and/or insulin resistance confer cardiovascular risk, particularly for diastolic dysfunction. Diabetes is associated with elevated myocardial norepinephrine (NE) content, enhanced sympathetic nervous system (SNS) activity, altered resting heart rate, and depressed heart rate variability. Positron emission tomography (PET) using the NE analogue [11C]meta-hydroxyephedrine ([11C]HED) provides an index of myocardial sympathetic neuronal integrity at the NE reuptake transporter (NET). The hypothesis of this project is that (i) hyperglycemia imparts heightened sympathetic tone and NE release, leading to abnormal sympathetic neuronal function in the hearts of diabetic rats, and (ii) these abnormalities may be reversed or prevented by treatments to normalize glycemia. Sprague Dawley rats were rendered insulin resistant by high fat feeding and diabetic by a single dose of streptozotocin (STZ). Diabetic rats were treated for 8 weeks with insulin, metformin or rosiglitazone, starting from either 1 week (prevention) or 8 weeks (reversal) after STZ administration. Sympathetic neuronal integrity was evaluated longitudinally by [11C]HED PET. Echocardiography measures of systolic and diastolic function were completed at serial timepoints. Plasma NE levels were evaluated serially and expression of NET and β-adrenoceptors were tested at the terminal endpoints. Diabetic rats exhibited a 52-57% reduction of [11C]HED standardized uptake value (SUV) at 8 weeks after STZ, with a parallel 2.5-fold elevation of plasma NE and a 17-20% reduction in cardiac NET expression. These findings were confirmed by ex vivo biodistribution studies. Transmitral pulse wave Doppler echocardiography established an extension of mitral valve deceleration time and elevated early to atrial velocity ratio, suggesting diastolic dysfunction. Subsequent treatment with insulin but not metformin restored glycemia, reduced plasma NE by 50%, normalized NET expression, and recovered [11C]HED SUV towards non-diabetic age-matched control. Diastolic dysfunction in these rats persisted. By contrast, early treatment with insulin, metformin, or rosiglitazone delayed the progression of diastolic dysfunction, but had no effect on elevated NE and reduced [11C]HED SUV in diabetic rats, potentially owing to a latent decrease in blood glucose. In conclusion, diabetes is associated with heightened circulating and tissue NE levels which can be effectively reversed by lowering glycemia with insulin. Noninvasive interrogation of sympathetic neuronal integrity using [11C]HED PET may have added value in the stratification of cardiovascular risk among diabetic patients and in determining the myocardial effects of glycemic therapy.

Orientador: Heitor Moreno Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T03:24:36Z (GMT). No. of bitstreams: 1 Santos_RodrigoCardoso_D.pdf: 1300897 bytes, checksum: 316736a36c07e5e655cecc5c8f664bdd (MD5) Previous issue date: 2013 / Resumo: Introdução: A disfunção diastólica do ventrículo esquerdo (DDVE) e a hipertrofia ventricular são consideradas marcadores frequentes para lesão cardíaca e fatores de risco de progressão para insuficiência cardíaca congestiva (ICC), especialmente em pacientes com hipertensão arterial resistente (HAR). A redução dos níveis pressóricos arteriais pode melhorar a disfunção diastólica do ventrículo esquerdo e os sintomas de insuficiência cardíaca. Entretanto, frequentemente esta redução não é atingida nos pacientes com HAR. Inibidores da fosfodiesterase 5 (PDE5) apresentam efeitos vasodilatadores discretos e, recentemente, se demonstrou que a administração de sildenafil a ratos hipertensos melhorou a disfunção diastólica do ventrículo esquerdo, através de ação direta sobre os miócitos cardíacos, evidenciando a presença de PDE5 neste tecido. Objetivo: Avaliar se o uso de um inibidor de PDE5 de longa duração (tadalafil) melhora a DDVE em pacientes com HAR de maneira independente de outros mecanismos secundários. Casuística e Métodos: Realizou-se um estudo intervencionista, cego, controlado por placebo, cruzado de uma via, incluindo 19 pacientes com HAR e DDVE. Inicialmente, receberam por via oral uma dose diária de placebo por 14 dias, com realização de medidas da pressão arterial de consultório e MAPA, avaliação da função endotelial (técnica de FMD), ecocardiograma e medidas de concentrações sanguíneas de BNP-32, GMPc e nitrito, antes e após o período de administração. Posteriormente, repetimos o mesmo procedimento, mas substituindo o placebo por tadalafil 20mg por dia. Ao final, as variáveis obtidas foram comparadas antes e após os usos de tadalafil e placebo, utilizando-se o método t de student pareado, com ?<0,05. Resultados: os pacientes apresentaram melhora da DDVE, demonstrada pela velocidade da onda E de 67,8±18,3cm/s para 77,8±16,0cm/s (p=0,025); relação E/A de 0,9±0,3 para 1,08±0,3 (p=0,01); tempo de desaceleração da onda E de 234,1±46,0ms para 194,4±43,3ms (p<0,01); tempo de relaxamento isovolumétrico de 128,7±17,6ms para 96,8±26,9ms (p<0,01); velocidade de onda E' lateral de 7,7±2,1cm/s para 8,8±2,8cm/s (p=0,025); velocidade de onda S' septal de 6,3±1,4cm/s para 7,7±1,7cm/s (p<0,01) e velocidade de onda S' lateral de 7,5±2,3cm/s para 8,3±2,2cm/s (p=0,014) (todas as variáveis expressas como em média e desvio-padrão). Houve, também, redução nos níveis de BNP-32 de 143±33,3 para 119,3±31,3 pg/mL e aumento no GMPc de 62,4±32,2 para 112,6±75,3pmol/mL. A concentração de nitrito foi semelhante com o uso de placebo e tadalafil. Em relação às medidas de pressão arterial, independentemente do método, também apresentam valores semelhantes antes e após o uso do fármaco, assim como a função endotelial. Os pacientes sob ação do placebo, não mostraram alterações em nenhuma das variáveis avaliadas. Conclusões: Os resultados sugerem que o uso de tadalafil melhora o relaxamento do ventrículo esquerdo em pacientes com HAR, independente da pressão arterial e da função endotelial, podendo constituir um importante tratamento adjunto em pacientes hipertensos sintomáticos com DDVE / Abstract: Introduction: Left ventricular hypertrophy and diastolic dysfunction (LVDD) remain frequent markers of cardiac damage and risk of progression to symptomatic heart failure (HF), especially in resistant hypertension (RHTN). Lowering BP may improve diastolic function and relieve HF symptoms; however, very often this target is not achieved in RHTN subjects. PDE-5 inhibitors have mild systemic vasodilatory effects, and recently, we demonstrated that administration of sildenafil in hypertensive rats improves LVDD, acting in cardiac myocytes with PDE5 expression in this tissue. Objective: To analyze if a long-acting PDE-5 inhibitor (tadalafil) may be clinically useful for improving LVDD in RHTN patients. Methods: We developed a single- blinded, placebo-controlled, one-way crossover, interventional study that enrolled 19 patients with RHTN and LVDD. At first, subjects were given a placebo daily oral dosage, for 2 weeks and they were submitted to blood pressure measurements (both ABPM and office), endothelial function (FMD) assessment, echocardiographic study and plasmatic BNP-32, cGMP and nitrite levels, before and after this 2-week period. Next, subjects were submitted to the same protocol receiving tadalafil (20 mg) orally instead of placebo. Variables were compared before and after placebo and tadalafil administration, using the paired student's t-test. The level of significance (?) accepted was less than 0.05. Results: Patients had an improvement in LVDD represented by changes in E-wave peak velocity from 67.8±18.3cm/s to 77.8±16.0cm/s (p=0.025), E/A ration from 0.9±0.3 to 1.08±0.3 (p=0.01), E wave deceleration time from 234.1±46.0ms to 194.4±43.3ms (p<0.001), isovolumic relaxation time from 128.7±17.6ms to 96.8±26.9ms (p<0.001), lateral E' wave velocity from 7.7±2.1cm/s to 8.8±2.8cm/s (p=0.025), septal S' wave velocity from 6.3±1.4cm/s to 7.7±1.7cm/s (p<0.01) and lateral S' wave velocity from 7.5±2.3cm/s to 8.3±2.2cm/s (p=0.014) (Values are expressed as mean ± standard deviation). We also noticed a decrease in BNP-32 levels from 143±33.3 to 119.3±31.3 pg/mL and an increase in cGMP levels from 62.4±32.2 to 112.6±75.3pmol/mL. No significant differences were detected in office and ABPM measurements, in endothelial function and nitrite levels. Conclusion: The current findings suggest that tadalafil enhances LV relaxation in resistant hypertensive patients and, despite its mild antihypertensive effect, may serve as an important adjunct to treat symptomatic hypertensive patients with evident LVDD / Doutorado / Farmacologia / Doutor em Farmacologia

Orientador: Paulo Sergio Patto dos Santos / Resumo: A nalbufina é um opioide agonista-antagonista com propriedades analgésicas adequadas e poucos efeitos depressores no sistema respiratório. Sua utilização na medicina veterinária é limitada pois muitos veterinários desconhecem suas vantagens. Além disso, seus efeitos na função cardíaca são pouco estudados. Portanto, com o estudo objetivou-se avaliar os efeitos da infusão contínua de nalbufina na função sistólica e diastólica do ventrículo esquerdo em cães saudáveis anestesiados com sevofluorano. Foram utilizados dezoito cães fêmeas de diversas raças ou sem raça definida, com idade média de 2 ± 1 anos e peso médio de 9,9 ± 3,8 kg. Os cães foram aleatoriamente submetidos a dois grupos denominados: nalbufina (GN) e controle (GC), com nove animais para cada grupo. Os animais foram induzidos e mantidos sob anestesia com sevofluorano (2V%). No GN foi administrado bolus intravenoso de nalbufina (0,3 mg/kg), seguido de infusão continua (0,4 mg/kg/h). O GC recebeu solução salina (NaCl 0,9%), em volumes idênticos em bolus e infusão ao GN. As variáveis ecocardiográficas de função sistólica e diastólica e os parâmetros hemodinâmicas foram determinadas no momento basal (antes do bolus) e 20, 40, 60 e 80 minutos após o início da infusão contínua. Não houve diferença entre os grupos para os parâmetros de função sistólica e diastólica ventricular esquerda derivados da ecocardiografia convencional e speckle tracking bidimensional. Do mesmo modo, as variáveis hemodinâmicas não apresentaram dife... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nalbuphine is an agonist-antagonist opioid with adequate analgesic properties and few depressant effects on the respiratory system. Its use in veterinary medicine is limited due to the unknown of its effects on cardiac function. The aim of this study was to assess the effects of a continuous rate infusion (CRI) of nalbuphine on left ventricular systolic and diastolic function of healthy sevoflurane-anesthetized dogs. Were used eighteen mixed-breed bitches ageging 2 ± 1 years and weighing 9.9 ± 3.8 kg. Dogs were randomly assigned to one of two groups: nalbuphine (GN, n=9); and control (GC, n=9). Anesthesia was induced and maintained with sevoflurane (2V%) followed by an intravenous (IV) bolus of nalbuphine (0.3 mg/kg) or 0.9% NaCl at equal volume, then CRI of nalbuphine (0.4 mg/kg/h) or 0.9% NaCl at equal infusion rate. Echocardiographic and hemodynamic variables were determined at baseline and 20, 40, 60 and 80 minutes following start of CRI. No differences were found between groups for left ventricular systolic and diastolic variables obtained through conventional echocardiography and two-dimensional speckle tracking. Likewise, hemodynamic variables did not differ between groups. The E′/A′ ratio significantly increased at 20 minutes compared to baseline only in GN. Nalbuphine given at a CRI does not influence left ventricular systolic and diastolic function in healthy sevoflurane-anesthetized dogs. / Doutor

Ischemic heart disease is a leading cause of death worldwide. Osteopontin (OPN), a cell-secreted extracellular matrix protein, is suggested to play a cardioprotective role in mouse models of ischemic heart disease. The objective of this study was to examine the role of OPN in modulation of systolic and diastolic functional parameters of the heart following mouse ischemia/reperfusion (I/R) injury. For this, wild-type (WT) and OPN-knockout (KO) mice aged approximately 4 months were subjected to cardiac ischemia for 45 minutes by the ligation of the left anterior descending coronary artery (LAD) followed by reperfusion of LAD by snipping the ligature. Heart function was measured using echocardiography at baseline, 1, 3, 7, 14, and 27 days post-I/R injury. M-mode echocardiographic images were used to calculate % fractional shortening [%FS], % ejection fraction [%EF], end-systolic volume [ESV], and end-diastolic volume [EDV], while pulsed wave Doppler images were used to measure aortic ejection time [AET], isovolumic relaxation time [IVRT], and total systolic time [TST]. Velocity of circumferential fiber shortening (Vcf) was calculated using FS and AET. I/R injury significantly decreased %EF and %FS in both WT and KO groups at all time points (1, 3, 7, 14, and 27 days post-I/R) versus the baseline. However, the decrease in % EF and %FS was significantly greater in KO-I/R group versus WT-I/R at 3, 7, 14 and 27 days post-I/R. I/R-mediated increase in ESV and EDV were significantly greater in KO-MI group versus WT-MI 3 day post-I/R. AET was significantly higher in WT-I/R group 27 days post-I/R versus baseline. However, AET was significantly lower in KO-I/R group 3 and 27 days post-I/R versus WT-I/R. IVRT was significantly higher in KO-I/R group 27 days post-I/R vs baseline. However, IVRT was significantly lower in KO-I/R group 1 day post-I/R vs WT-I/R. TST remained unchanged in WT and KO groups post-I/R versus their respective baseline groups. However, TST was significantly lower in KO-I/R group versus WT-I/R at 3 days post-I/R. Vcf was significantly higher at basal levels in the KO versus WT mice. I/R injury decreased Vcf in both groups versus their baseline at all time-points. These data provide evidence that lack of OPN deteriorates systolic and diastolic functional parameters of the heart following I/R injury, suggesting a cardioprotective role of OPN in myocardial remodeling post-IR.

Accumulating evidence reveals that albuminuria may exacerbate uncontrolled blood pressure (BP) in hypertensive patients. However, racial differences in the associations of albuminuria with uncontrolled BP among diagnosed hypertensives have not been evaluated. A total of 6147 diagnosed hypertensive subjects aged ≥18 years were collected from the National Health and Nutrition Examination Survey 1999-2008 with stratified multistage sampling designs. Odds ratios (ORs), relative ORs and 95% confidence intervals (CIs) in uncontrolled BP, and the different effects of microalbuminuria and macroalbuminuria on continuous BP were estimated using weighted logistic models and linear regression models. Hypertensive subjects with microalbuminuria and macroalbuminuria were more likely to have uncontrolled BP and higher average systolic BP (SBP) in all individual racial groups. Microalbuminuria was associated with isolated uncontrolled SBP in non-Hispanic blacks and whites, and macroalbuminuria was associated with isolated uncontrolled SBP and diastolic BP (DBP) and high average DBP only in non-Hispanic blacks. Compared with non-Hispanic whites, non-Hispanic blacks and Mexicans had lower associations of microalbuminuria with uncontrolled BP (relative OR=0.68, 95% CI=0.48-0.97 for blacks vs whites; relative OR=0.62, 95% CI=0.42-0.93 for Mexicans vs. whites) and isolated uncontrolled SBP (relative OR=0.62, 95% CI=0.43-0.90 for blacks vs. whites; relative OR=0.45, 95% CI=0.29-0.71 for Mexicans vs. whites). The association of microalbuminuria with uncontrolled BP was lower in non-Hispanic blacks and Mexicans than in non-Hispanic whites. Health providers need to improve care for mildly elevated albumin excretion rates in non-Hispanic white hypertensive patients while maintaining the quality of care in non-Hispanic blacks and Mexicans.

Accumulating evidence reveals that albuminuria may exacerbate uncontrolled blood pressure (BP) in hypertensive patients. However, racial differences in the associations of albuminuria with uncontrolled BP among diagnosed hypertensives have not been evaluated. A total of 6147 diagnosed hypertensive subjects aged ≥18 years were collected from the National Health and Nutrition Examination Survey 1999-2008 with stratified multistage sampling designs. Odds ratios (ORs), relative ORs and 95% confidence intervals (CIs) in uncontrolled BP, and the different effects of microalbuminuria and macroalbuminuria on continuous BP were estimated using weighted logistic models and linear regression models. Hypertensive subjects with microalbuminuria and macroalbuminuria were more likely to have uncontrolled BP and higher average systolic BP (SBP) in all individual racial groups. Microalbuminuria was associated with isolated uncontrolled SBP in non-Hispanic blacks and whites, and macroalbuminuria was associated with isolated uncontrolled SBP and diastolic BP (DBP) and high average DBP only in non-Hispanic blacks. Compared with non-Hispanic whites, non-Hispanic blacks and Mexicans had lower associations of microalbuminuria with uncontrolled BP (relative OR=0.68, 95% CI=0.48-0.97 for blacks vs whites; relative OR=0.62, 95% CI=0.42-0.93 for Mexicans vs. whites) and isolated uncontrolled SBP (relative OR=0.62, 95% CI=0.43-0.90 for blacks vs. whites; relative OR=0.45, 95% CI=0.29-0.71 for Mexicans vs. whites). The association of microalbuminuria with uncontrolled BP was lower in non-Hispanic blacks and Mexicans than in non-Hispanic whites. Health providers need to improve care for mildly elevated albumin excretion rates in non-Hispanic white hypertensive patients while maintaining the quality of care in non-Hispanic blacks and Mexicans.

Increasing diastolic dysfunction (DD) grade is associated with increased heart failure (HF). Patients with preserved ejection fractions and grade 1 DD may have left atrial dilatation, e′ < 8 cm/sec, increased left ventricular (LV) mass, or variable E/e′ ratios. The aim of this study was to test the hypothesis that LV hypertrophy or E/e′ ratio > 8 may be associated with a greater incidence of HF. Methods Two hundred twelve patients with grade 1 DD and ejection fractions > 50% were retrospectively studied. Group 1 comprised 108 patients with E/A ratios < 0.8, without LV hypertrophy, e′ < 8 cm/sec, and E/e′ ratios < 8. Group 2 comprised 104 patients with LV hypertrophy or E/e′ ratios > 8. Patients with incident HF and valvular or coronary disease were excluded. Using two-dimensional Doppler echocardiography, LV and left atrial volumes and transmitral spectral and tissue Doppler were analyzed. Medical records were examined for laboratory data, HF admissions, and all-cause mortality from 2004 to 2012. Results Despite similar ejection fractions, patients in group 2 had greater LV and left atrial volumes, LV mass index values, and E/e′ ratios (P < .01 for all). HF incidence was greater in group 2 (30 vs 4, P < .001). Combined HF or all-cause mortality was greater in group 2 (46 vs 14, P < .001). Multivariate analysis revealed that HF was associated with E/e′ ratio (P < .0001), systolic blood pressure (P = .0123), and LV mass index (P = .042). Combined HF or all-cause mortality was associated with E/e′ ratio (P < .0001), LV mass index (P = .009), and lower calcium channel blocker use (P = .0011). Conclusions HF alone or HF and all-cause mortality were increased in patients with grade 1 DD in the presence of LV hypertrophy or elevated LV filling pressures.

Diabetes causes cardiomyopathy and increases the risk of heart failure independent of hypertension and coronary heart disease. This condition called “Diabetic Cardiomyopathy” (DCM) is becoming a well- known clinical entity. Recently, there has been substantial research exploring its molecular mechanisms, structural and functional changes, and possible development of therapeutic approaches for the prevention and treatment of DCM. This review summarizes the recent advancements to better understand fundamental molecular abnormalities that promote this cardiomyopathy and novel therapies for future research. Additionally, different diagnostic modalities, up to date screening tests to guide clinicians with early diagnosis and available current treatment options has been outlined.

Left ventricular diastolic dysfunction (LVDD) is any abnormality in the filling of the left ventricle (LV).  Despite the prevalence of this disease, it remains difficult to diagnose, mainly due to inherent compensatory mechanisms and a limited physical understanding of the filling process.  LV filling can be non-invasively imaged using color m-mode echocardiography which provides a spatio-temporal map of inflow velocity.  These filling patterns, or waves, are conventionally used to qualitatively assess the filling pattern, however, this work aims to physically quantify the filling waves to improve understanding of diastole and develop robust, reliable, and quantitative parameters. This work reveals that LV filling waves in a normal ventricle act as dispersive waves and not only propagate along the length of the LV but also spread and disperse in the direction of the apex.  In certain diseased ventricles, this dispersion is limited due to changes in LV geometry and wall motion.  This improved understanding could aid LVDD diagnostics not only for determining health and disease, but also for distinguishing between progressing disease states. This work also identifies a limitation in a current LVDD parameter, intra ventricular pressure difference (IVPD), and presents a new methodology to address this limitation.  This methodology is also capable of synthesizing velocity information from a series of heartbeats to generating one representative heartbeat, addressing inaccuracies due to beat-to-beat variations.  This single beat gives a comprehensive picture of that specific patient's filling pattern.  Together, these methods improve the clinical utility of IVPD, making it more robust and limiting the chance for a misdiagnosis. / Master of Science