Abstract Ischemic stroke is associated with cardiovascular autonomic nervous system (ANS) disturbances, including reduced heart rate (HR) variability and acute phase neurohumoral activation with elevated stress hormone levels. The impact of HR variability and neurohumoral factors such as natriuretic peptides on the long-term survival of patients with ischemic stroke has not been studied previously. This study was designed to evaluate cardiovascular autonomic regulation in ischemic stroke patients by assessing HR dynamics and various neurohumoral factors. The values of the assessed variables in predicting mortality were evaluated. HR variability assessments were performed in the acute phase of ischemic stroke and for a general elderly population. Various neurohumoral factors were also assessed in the acute phase of stroke. After follow-up, the survival of the subjects was assessed and the prognostic values of the measured factors were evaluated. Stroke patients were found to have cardiovascular autonomic and hormonal disturbances manifested as reduced traditional time and frequency domain measures of HR variability, altered long-term HR dynamics and elevated levels of natriuretic peptides in the acute phase. Altered long-term HR dynamics in the acute phase of stroke predicted long-term mortality after stroke and cerebrovascular mortality in the general elderly population. Neuroendocrine activation involving elevated natriuretic peptide values that were associated with high cortisol and catecholamine levels was observed in the acute phase of ischemic stroke. Neurohumoral disturbance was prognostically unfavourable. The most powerful predictors of poststroke mortality were altered long-term HR dynamics and elevated levels of natriuretic peptides and cortisol, which predicted mortality independently of the conventional risk factors in multivariate analysis. Prognostically unfavourable cardiovascular autonomic dysfunction with disturbances in the long-term behaviour of HR dynamics was found to be related to ischemic stroke. Neurohormonal activation with elevated natriuretic peptide and cortisol levels in the acute phase predicts long-term mortality after ischemic stroke.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20979号 / 医博第4325号 / 新制||医||1026(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妻木 範行, 教授 戸口田 淳也, 教授 柳田 素子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

Sex dimorphism in the prevalence, onset, development and progression of cardiovascular disease (CVD) is well recognized. Sex-specific differences in adaptation to cardiac pathological progressions such as cardiac hypertrophy (CH), and the extent to which they are attributable to sex hormones requires further delineation. The objective of this dissertation was to determine which cardiac vasoactive systems are responsible for sex-specific differences in CH modulation using the atrial natriuretic peptide gene-disrupted (ANP-/-) mouse model. First, sex-specific differences in the expression of the cardiac natriuretic peptide (NP) and nitric oxide synthase (NOS) systems were evaluated. Next, the influence of 17β-Estradiol (E2) on the expression and signaling of the cardiac NP and NOS systems was determined in ovariectomized (OVX) female ANP+/+ and ANP-/- mice. Finally, sex-specific differences in cardiac adaptation to Angiotensin II (ANGII) pressure overload were elucidated in male and intact female ANP+/+ and ANP-/- mice. These studies revealed that males predominantly use the NP system and females predominantly use the NOS system. Sex-specific differences in the cardiac NOS system were further enhanced by E2 in OVX female ANP+/+ and ANP-/- mice. In the female ANP-/- mouse, E2 was found to signal through the NOS system to significantly increase plasma cGMP. Finally, male and female differences were demonstrated in the sex-specific patterns of cardiac vasoactive gene system expression and development of cardiac dysfunction in response to ANGII treatment. Sex dimorphism was observed in the expression of BNP and NPR-A in male and female ANP-/- mice treated with ANGII. Female ANP+/+ and ANP-/- ANGII-treated mice exhibited elevated E/E’ ratios that were not found to the same extent in genotype matched ANGII-treated male mice, demonstrating that female mice developed ANGII-mediated mild left ventricle diastolic dysfunction. Based on the results of this dissertation, we conclude that sex-specific differences do indeed exist in the cardiac adaptation to pathological stresses. These data support the understanding that a progression towards sex-specific CVD treatments is warranted, with a particular emphasis on the potential benefits of female-specific targeting of the cardiac NOS system. / Thesis (Ph.D, Anatomy & Cell Biology) -- Queen's University, 2013-08-23 14:21:45.324

by Tung Sin Yi, Cindy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 117-132). / Acknowledgements --- p.I / List of Abbreviations --- p.II / Abstract --- p.IV / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Astrocytes in the Central Nervous System (CNS) l / Chapter 1.1.1 --- Characteristics of astrocytes / Chapter 1.1.2 --- Functions of astrocytes / Chapter 1.1.2.1 --- General functions of astrocytes / Chapter 1.1.2.2 --- Effects of neuroactive peptides on astrocytes / Chapter 1.1.3 --- Gliomas and the rat C6 glioma cells / Chapter 1.2 --- C-Type natriuretic peptide (CNP) in the CNS --- p.9 / Chapter 1.2.1 --- Structure and distribution of natriuretic peptides in the CNS / Chapter 1.2.2 --- Actions of CNP / Chapter 1.2.3 --- Natriuretic peptide receptors and signal transduction in astrocytes / Chapter 1.3 --- Endothelin-3 (ET-3) in the CNS --- p.18 / Chapter 1.3.1 --- Structure and distribution of endothelins (ETs) in the CNS / Chapter 1.3.2 --- Actions of ET-3 / Chapter 1.3.3 --- Endothelin receptors and signal transductionin astrocytes / Chapter 1.4 --- cGMP second messenger system in astrocytes --- p.28 / Chapter 1.4.1 --- Second messenger systems in astrocytes / Chapter 1.4.2 --- cGMP as second messenger in astrocytes / Chapter 1.4.3 --- Post cGMP cascade effects / Chapter 1.5 --- The aims of this project --- p.33 / Chapter Chapter 2 --- Methods / Chapter 2.1 --- In vitro culture of rat C6 glioma cells --- p.36 / Chapter 2.1.1 --- Preparation of reagents / Chapter 2.1.2 --- Culture of C6 glioma cells / Chapter 2.1.3 --- "Cell plating in 6-well, 24-well and 96-well plastic trays" / Chapter 2.2 --- Determination of cGMP --- p.40 / Chapter 2.2.1 --- Measurement of cGMP / Chapter 2.2.2 --- Data analysis / Chapter 2.3 --- Determination of the effect of CNP on cGMP productionin C6 cells --- p.41 / Chapter 2.4 --- Determination of the effect of ET-3 on the action of CNPin C6cells --- p.44 / Chapter 2.4.1 --- Measurement of intracellular cGMP levels affected by ET-3 / Chapter 2.4.2 --- Measurement of intracellular cGMP levels affected by CNP with ET-3 pretreatment / Chapter 2.5 --- Determination of the effects of PKC activator and inhibitor on CNP-treated C6 cells --- p.46 / Chapter 2.5.1 --- Measurement of intracellular cGMP levels affected by PKC activator or inhibitor / Chapter 2.5.2 --- Measurement of intracellular cGMP levels affected by CNP with PKC activator or inhibitor pretreatment / Chapter 2.5.3 --- Measurement of intracellular cGMP levels affected by CNP with PKC inhibitor antagonized PMA or ET-3 pretreatment / Chapter 2.6 --- Determination of the effect of arachidonic acid on the action of CNP in C6 cells --- p.49 / Chapter 2.7 --- Determination of the effects of ET-3 and CNP on calcium uptake in C6 cells --- p.50 / Chapter 2.8 --- Determination of the effects of CNP and ET-3 on cell volume change in C6 cells --- p.51 / Chapter 2.9 --- Determination of the effects of CNP and ET-3 on glucose and amino acids uptake in C6 cells --- p.53 / Chapter 2.9.1 --- Measurement of glucose uptake in CNP - and/or ET- 3-treated C6 cells / Chapter 2.9.2 --- Measurement of amino acids uptake in CNP - and/or ET-3-treated C6 cells / Chapter 2.10 --- "Determination of thymidine, uridine and leucine incorporation in CNP - and/or ET-3- treated C6 cells" --- p.55 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Effects of CNP and ET-3 on cGMP production in cultured rat C6 glioma cells --- p.56 / Chapter 3.1.1 --- Effect of CNP on cGMP production in cultured C6 glioma cells --- p.57 / Chapter 3.1.1.1 --- The time course of CNP on cGMP production / Chapter 3.1.1.2 --- Dosage-response of CNP on cGMP production / Chapter 3.1.2 --- Effect of ET-3 on cGMP production in C6 glioma cells --- p.61 / Chapter 3.1.2.1 --- Effect of ET-3 on basal cGMP production / Chapter 3.1.2.2 --- Effect of pre-exposure duration to ET-3 on CNP-induced cGMP formation / Chapter 3.1.2.3 --- Dosage-response of ET-3 on CNP-induced cGMP production / Chapter 3.1.3 --- Effect of PMA on cGMP production in C6 glioma cells --- p.65 / Chapter 3.1.3.1 --- Effect of PMA on basal cGMP production / Chapter 3.1.3.2 --- Effect of pre-exposure duration to PMA on CNP-induced cGMP formation / Chapter 3.1.3.3 --- Dosage-response of PMA on CNP-induced cGMP production / Chapter 3.1.4 --- Effects of PKC inhibitors on cGMP production in C6 glioma cells --- p.73 / Chapter 3.1.4.1 --- Effects of PKC inhibitors on basal cGMP production / Chapter 3.1.4.2 --- Effects of PKC inhibitors on CNP-induced cGMP formation / Chapter 3.1.4.3 --- Antagonism of PKC inhibitors on the action of PMA on CNP-induced cGMP formation / Chapter 3.1.4.4 --- Antagonism of PKC inhibitors on the action of ET-3 on CNP-induced cGMP formation / Chapter 3.1.5 --- Effect of arachidonic acid on CNP-induced cGMP production in C6 glioma cells --- p.82 / Chapter 3.2 --- Effects of CNP and ET-3 on cellular metabolism in cultured rat C6 glioma cells --- p.83 / Chapter 3.2.1 --- Effects of CNP and ET-3 on calcium uptake in C6 glioma cells --- p.86 / Chapter 3.2.2 --- Effects of CNP and ET-3 on cell volume changes in C6 glioma cells --- p.89 / Chapter 3.2.3 --- Effects of CNP and ET-3 on glucose and amino acids uptake in C6 glioma cells --- p.91 / Chapter 3.2.4 --- Effects of CNP and ET-3 on C6 cell proliferation --- p.98 / Chapter 3.2.5 --- Effects of CNP and ET-3 on RNA synthesis --- p.101 / Chapter 3.2.6 --- Effects of CNP and ET-3 on protein synthesis --- p.103 / Chapter Chapter 4 --- Discussion and Conclusion --- p.105 / References --- p.117

C-type natriuretic peptide (CNP) is synthesised and released by the endothelium and plays a vital role in the maintenance of vascular homeostasis (Moyes et al., 2014). However, a similar regulatory role of endogenous CNP in the heart has yet to be elucidated. Therefore, I have used three unique mouse strains with endothelium (Tie2-Cre), cardiomyocyte (αMHC-Cre) and fibroblast (Col1α2-Cre)-restricted deletion of CNP to investigate if the peptide modulates coronary vascular reactivity and cardiac function. Methods: Langendorff isolated hearts were used to investigate the effect of CNP deletion on coronary vascular reactivity in response to the endothelium-dependent vasodilators bradykinin (10nmol) and acetylcholine (0.1-1nmol). Vasodilatation associated with reperfusion was investigated by transient cessation of flow (20-80 seconds). Ischaemia reperfusion (IR) injury (35 minutes ischaemia followed by 60 minutes reperfusion) was also investigated in cell-specific knockout (KO) animals. Isoprenaline (ISO; 20mg/kg/day, 7days)- and pressure overload (abdominal aortic constriction [AAC]; 6 weeks)-induced heart failure were used to study the effect of CNP deletion during cardiac stress, with cardiac function assessed by echocardiography. Cardiac fibrosis and hypertrophy were determined by picro-sirius red and wheat-germ agglutinin fluorescence staining, respectively. A subset of experiments was repeated in mice with global deletion of natriuretic peptide receptor-C (NPR-C) to delineate the signalling pathway triggered by CNP. Real time qPCR was used to determine hypertrophic and fibrotic gene expression in left ventricles isolated from mice subjected to AAC or sham. Neonatal cardiomyocytes were isolated to investigate angiotensin (Ang)II-induced hypertrophy. Results: Coronary endothelial reactivity was reduced in endothelial CNP (ecCNP) KO mice compared to wild type (WT) in response to bradykinin, acetylcholine and reperfusion-induced vasodilatation. These observations were paralleled in NPR-C KO animals. ecCNP KO did not exacerbate IR injury, whilst mice with cardiomyocyte-restricted deletion of CNP (cmCNP KO) and NPR-C KO animals exhibited a larger infarct size compared to WT. cmCNP KO mice also displayed greater cardiac dysfunction and fibrosis after ISO infusion or AAC compared to WT; similar results were observed in fbCNP KO and NPR-C KO animals. Infusion of CNP (0.2mg/kg/day; osmotic mini-pump, s.c.) in WT, but not NPR-C KO, animals rescued the decline in cardiac function. CNP (1μM) administration in isolated cardiomyocyte also blunted Ang II-induced hypertrophy. Pro-hypertrophic and pro-fibrotic gene expression (ANP, β-MHC and MMP-2) was augmented in cmCNP KO and NPR-C KO mice compared to littermate controls following AAC. Conclusions: Endothelial, cardiomyocyte and fibroblast-derived CNP have distinct, complementary roles in the heart, modulating cardiac function by influencing coronary vascular tone and protecting against heart failure and IR injury. These protective effects of CNP are mediated, at least in part, via NPR-C activation. Developing CNP mimetics or selective NPR-C agonists could be a novel therapeutic intervention in cardiovascular disease.

In dieser post-hoc Analyse der Deutschen Diabetes und Dialyse Studie wurde der Einfluss von NT-proBNP und Troponin T auf plötzlichen Herztod, Schlaganfall, Myokardinfarkt und die Gesamtmortalität während vierjähriger Studiendauer bei 1255 Patienten mit Diabetes mellitus Typ 2 an der Hämodialyse analysiert. Des Weiteren wurde die Bedeutung einer longitudinalen Messung der Biomarker nach 6 Monaten auf die Endpunkte untersucht. Patienten mit dem höchsten NT-proBNP respektive Troponin T wiesen die größte Ereignisrate für plötzlichen Herztod, Schlaganfall und die Gesamtmortalität auf. In der multivariaten Regressionsanalyse waren sowohl NT-proBNP als auch Troponin T jeweils starke unabhängige Prädiktoren für plötzlichen Herztod, Schlaganfall und die Gesamtmortalität. Eine Assoziation von NT-proBNP mit dem Auftreten von Myokardinfarkten wurde nicht gesehen. Nicht nur ein hoher Ausgangswert der Biomarker, sondern auch eine Zunahme von NT-proBNP und Troponin T nach 6 Monaten waren assoziiert mit einer schlechteren Langzeitprognose / This post-hoc analysis of the German Diabetes and Dialysis study examined the effect of baseline and change from baseline after 6 months of NT-proBNP and Troponin T on sudden death, stroke, myocardial infarction, and all-cause mortality in 1255 hemodialysis patients with type 2 diabetes mellitus with a median follow up of 4 years. Patients with increasing baseline NT-proBNP and Troponin T exhibited a higher risk of sudden death, stroke, and all-cause mortality. In multivariate regression analysis both, NT-proBNP and Troponin T, were independent predictors of sudden death, stroke, and all-cause mortality. Neither baseline nor change in NT-proBNP was significantly associated with myocardial infarction. Increased longitudinal levels of NT-proBNP and Troponin T during follow up were associated with higher risks of adverse cardiovascular outcomes and death.

Abstract not available

<p>Plant natriuretic peptides (PNPs) are a novel class of extracellular, systemically mobile molecules that elicit a number of plant responses important in homeostasis and growth. Natriuretic peptides were first identified in vertebrates where they play a role in the regulation of salt and water balance. Subsequent experimental investigations have identified the presence of a natriuretic peptide hormone system in plants. While PNPs have been implicated in various physiological responses such as stomatal guard cell movements and regulation of net water uptake, its biological role has remained elusive. Here we have used co-expression and promoter content analysis tools to understand the biological role of the Arabidopsis thaliana PNP (AtPNP-A). The analysis of AtPNP-A and its co-expressed genes revealed that genes annotated as part of the systemic acquired resistance (SAR) pathway were over-represented, thus suggesting that AtPNP-A may function as a component of plant defense responses and specifically, SAR. The results further show that AtPNP-A shares many characteristics with pathogenesis related (PR) proteins in that its transcription is strongly induced in response to pathogen challenges, thus implying a newly described role for AtPNP-A in pathogen attack. Additional tissue expression analysis also indicated distinct localization of PNP activity in sepals and transcriptional meta-analysis showed that AtPNP-A may play a role in starch breakdown. Therefore, together with the finding that AtPNP-A plays a role in regulating phloem transport, we also hypothesize that AtPNP-A may play a role in phloem unloading in sepals to assist processes such as seed formation in plants. In plants, the second messenger, guanosine 3&rsquo / ,5&rsquo / -cyclic monophosphate (cGMP) mediates a whole range of important processes including salinity tolerance, disease resistance, drought tolerance and responses to light. Since PNPs regulate water and salt homeostasis via a cGMP-dependent signaling pathways, it is thus important to analyse the transcriptome induced by the second messenger (cGMP) in Arabidopsis thaliana to give a better understanding of its mechanism of action. This study was also supplemented by the analysis of the gibberellic acid (GA) dependent transcriptome, since cGMP also plays a role its transcription pathway. This data analysis, together with promoter content investigation, revealed that genes upregulated after cGMP treatment and down-regulated in the GA insensitive mutant (ga1-3) were enriched with a GA response element (GARE), while no GARE enrichment were observed in genes up-regulated in the ga1-3 mutant. These findings suggest that GARE is indicative of GA-induced and cGMP-dependent transcriptional up-regulation. Gene ontology analysis confirmed previous reports that cGMP is involved in ion homeostasis and indicated that the transcriptional cGMP response is bi-polar in the sense that both genes up- and down-regulated in response to cGMP is involved in cation transport. Additionally, ab initio analysis of genes transcriptionally dependent on cGMP identified CHX8 as a hub gene and promoter content of CHX8 co-expressed genes show enrichment of the GARE motif. The fact that CHX8 has its highest expression levels during male gametogenesis and pollen tube growth, together with our findings, suggest that GA-induced and cGMP- dependent genes may play a key role in ion and water homeostasis in the male gametophyte. Finally, we propose that the type of analysis undertaken here can yield new insights into gene regulation networks and inform experimental strategies to unravel complex transcription regulatory systems under different developmental and stimulus specific conditions.</p>