Eine der häufigsten kardiovaskulären Erkrankungen ist die Atherosklerose. Bei der Entstehung einer Atherosklerose spielt eine Hyperlipoproteinämie eine entscheidende Rolle. Ein weiterer Faktor für die Entstehung kardiovaskulärer Erkrankungen ist ein hoher Blutdruck. In dieser Arbeit wurde eine mögliche Interaktion zwischen Lipoproteinen und den blutdruckregulierenden Endothelin- und Renin-Angiotensin-Systemen untersucht. Weiterführende Analysen erfolgten an Rezeptoren für die Aufnahme von nLDL und oxLDL. Abschließend wurden Signalwege untersucht, die durch nLDL und oxLDL aktiviert werden. Tierexperimentielle Untersuchungen in Aorten und Herzen fettreich gefütterter Wildtyp- Mäuse unterstützen die Zellkultur-Ergebnisse einer Induzierung des Endothelin-Systems durch erhöhte Lipoproteine. Zusammenfassend zeigt diese Arbeit neue Mechanismen der Interaktion von Lipoproteinen und blutdruckregulierenden Systemen in Endothelzellen. Die Rezeptoren scheinen dabei eine Schlüsselrolle zu spielen. Dies spricht für eine Potenzierung von Hyperlipoproteinämie und Hypertonie bei der Entstehung von Herz-Kreislauf-Erkrankungen.

The mechanisms whereby the pituitary gland maintains arterial pressure were investigated in rats. The arterial pressure in hypophysectomized rats was 30 mmHg below normal. Saralasin or captopril caused a further fall of 25 and 30 mmHg, respectively, suggesting that the renin-angiotensin system plays a role in blood pressure maintenance in hypophysectomized rats. Growth hormone administration to hypophysectomized rats increased the arterial pressure, but pretreatment with captopril prevented the effect. Plasma renin activity and basal renin secretion (in vitro) was normal in hypophysectomized rats despite a twofold greater renal renin content. Secretory responsiveness to isoproterenol and calcium omission was lower in hypophysectomized rats. It is concluded that the renin-angiotensin system plays a role in maintaining arterial blood pressure in hypophysectomized rats although the responsiveness of the system may be decreased.

In dieser Arbeit wurden 8 und 16 Wochen alte, hypertensive "fawn-hooded" Ratten (FHH8, FHH16) mit genetisch ähnlichen 16 Wochen alten "fawn-hooded" Ratten mit nur geringgradiger Blutdruckerhöhung (FHL16, Kontrollgruppe) hinsichtlich der pathologisch-anatomischen Veränderungen der Nierenmorphologie und hinsichtlich der Expression von NO-Synthase-1 (NOS1), Cyclooxygenase-2 (COX-2) und Renin am juxtaglomerulären Apparat (JGA) verglichen. Die histopathologischen Veränderungen bei FHH16 umfassten die klassischen Schädigungszeichen der fokal segmentalen Glomerulosklerose (FSGS) mit fokaler Überexpression von Kollagen IV und eine moderate Arteriolopathie. Bei FHH8 ließen sich, wie bei FHL16 keine morphologischen Schädigungen nachweisen. Die NOS1-Aktivität an der Macula densa, untersucht mittels der NADPH-Diaphorasereaktion und die NOS1 mRNA Expression waren bei FHH8 (+153 and +88%; P < 0.05) und FHH16 (+93 and +98%; P < 0.05) im Vergleich zu FHL16 signifikant erhöht. Eine gleichgerichtete signifikante Erhöhung zeigte sich für die COX-2-Expression an der Macula densa von FHH8 (+166%; P < 0.05) und FHH16 (+157%; P < 0.05) im Vergleich zu FHL16. Des weiteren ließ sich eine signifikante, ebenfalls gleichgerichtete Überexpression von Renin in der afferenten Arteriole auf Protein- und mRNA-Ebene bei FHH8 (+51 and +166%; P < 0.05) und FHH16 (+105 and +136%; P < 0.05) im Vergleich zu FHL16 nachweisen. Somit konnte gezeigt werden, dass die gleichgerichtete Überexpression von NOS1, COX-2 und Renin am JGA bei der FHH-Ratte der Entwicklung einer fokal segmentalen Glomerulosklerose vorausgeht und damit möglicherweise pathogenetische Bedeutung für die Entstehung der Nierenschädigung bei diesem Rattenstamm hat. / This study describes elevated histochemical signals for nitric oxide synthase-1 (NOS1) and cyclooxygenase-2 (COX-2) in juxtaglomerular apparatus (JGA) and adjacent thick ascending limb of the kidney of fawn-hooded hypertensive rats (FHH). Two different age groups of FHH (8 and 16 wk; FHH8 and FHH16, respectively) were compared with genetically related fawn-hooded rats with close to normal blood pressure (FHL) that served as controls. Histopathological changes in FHH16 comprised focal segmental glomerulosclerosis (FSGS), focal matrix overexpression (mainly of collagen IV), and a moderate arteriolopathy with hypertrophy of the media, enhanced immunoreactivity for alpha-smooth muscle actin, and altered distribution of myofibrils. Macula densa NOS activity, as expressed by NADPH-diaphorase staining, and NOS1 mRNA abundance were significantly elevated in FHH8 (+153 and +88%; P < 0.05) and FHH16 (+93 and +98%; P < 0.05), respectively. Even higher elevations were registered for COX-2 immunoreactivity in FHH8 (+166%; P < 0.05) and FHH16 (+157%; P < 0.05). The intensity of renin immunoreactivity and renin mRNA expression in afferent arterioles was also elevated in FHH8 (+51 and +166%; P < 0.05) and FHH16 (+105 and +136%; P < 0.05), respectively. Thus we show that coordinate upregulation of tubular NOS1, COX-2, and renin expression precedes, and continues after, the manifestation of glomerulosclerotic damage in FHH. These observations may have implications in understanding the role of local paracrine mediators in glomerular disease.

O sistema renina-angiotensina (SRA) circulante é um sistema endócrino que promove a produção de angiotensina (Ang) II, a qual exerce seus efeitos pela interação com receptores específicos. O conceito clássico do SRA circulante está sendo modificado, pois tem sido demonstrada a existência de sistemas locais capazes de gerar angiotensinas de forma independente do SRA circulante em vários tecidos e órgãos. Trabalhos recentes sugerem a existência de alguns componentes do SRA em tecido gengival e fibroblastos gengivais de diferentes espécies. Porém, não são encontrados na literatura achados inequívocos sobre a presença de importantes componentes do SRA, tais como renina e angiotensinogênio, no tecido gengival de rato. Portanto, os objetivos do presente trabalho foram: 1) estudar a expressão e localização de componentes do SRA no tecido gengival de rato e 2) estudar in vitro a funcionalidade do SRA local em homogenato de tecido gengival de rato quanto à formação de Ang II e outros peptídeos vasoativos a partir de precursores de Ang II. Transcrição reversa seguida de reação em cadeia da polimerase (RTPCR) foi utilizada para avaliar a expressão de RNAm. Análise imunohistoquímica foi utilizada para detecção e localização de renina no tecido gengival de rato. Um método fluorimétrico padronizado com o tripeptídeo Hipuril-Histidina-Leucina (Hip-His-Leu) foi usado para medir a atividade da ECA em homogenatos de tecido gengival de rato. A técnica de cromatografia líqüida de alto desempenho (HPLC) foi usada para analisar os produtos formados após a incubação de homogenatos de tecido gengival de rato com Ang I ou tetradecapeptídeo substrato de renina (TDP). RT-PCR revelou a expressão de RNAm para renina, angiotensinogênio, ECA e receptores de Ang II (AT1a, AT1b e AT2) em tecido gengival; em fibroblastos cultivados de tecido gengival foi observada expressão de RNAm para renina, angiotensinogênio e receptor AT1a. A técnica de imunohistoquímica demonstrou a existência de renina em vasos de tecido gengival de rato. Atividade da ECA foi detectada por meio do ensaio fluorimétrico (4,95±0,89 nmol His-Leu/g.min). Quando Ang I foi usada como substrato, análises de HPLC mostraram a formação de Ang 1-9 (0,576±0,128 nmol/mg.min), Ang II (0,066±0,008 nmol/mg.min) e Ang 1-7 (0,111±0,017 nmol/mg.min), enquanto que os mesmos peptídeos (0,139±0,031; 0,206±0,046 e 0,039±0,007 nmol/mg.min, respectivamente) e Ang I (0,973±0,139 nmol/mg.min) foram formados quando TDP foi usado como substrato. Adicionalmente, análises de HPLC revelaram a ausência de enzimas que degradam Ang II em homogenatos de tecido gengival de rato. Em conclusão, os resultados apresentados neste trabalho mostram claramente a existência de um SRA local em tecido gengival de rato, que é capaz de gerar Ang II e outros peptídeos vasoativos in vitro. Estudos adicionais são necessários para elucidar o papel deste sistema local no tecido gengival de rato. / Systemic renin-angiotensin system (RAS) promotes the plasmatic production of angiotensin (Ang) II, which acts through the interaction with specific receptors. The concept of this classic circulating RAS has been modified since there is growing evidence that local systems in various tissues and organs are capable of generating angiotensins independently of the circulating RAS. Recent works suggest the existence of some RAS components in the gingival tissue and cultured gingival fibroblasts of different species, but there is paucity of data in the literature regarding the unequivocal existence of crucial RAS components, such as renin and angiotensinogen, in the rat gingival tissue. Therefore, the aims of the present work were to: 1) study the expression and localization of RAS components in the rat gingival tissue and 2) evaluate the in vitro production of Ang II and other peptides catalyzed by rat gingival tissue homogenates incubated with different precursors of Ang II. Reverse transcription-polymerase chain reaction (RT-PCR) was used to assess mRNA expression. Immunohistochemical (IHC) analysis aimed to detect and localize renin in the rat gingival tissue. A standardized fluorimetric method with the tripeptide Hippuryl-Histidyl-Leucine (Hip-His-Leu) was used to measure tissue ACE activity in rat gingival tissue homogenates. High performance liquid chromatography (HLPC) was used to analyze the products formed after the incubation of rat gingival tissue homogenates with Ang I or tetradecapeptide renin substrate (TDP). RT-PCR revealed the mRNA expression for renin, angiotensinogen, ACE and Ang II receptors (AT1a, AT1b and AT2) in the rat gingival tissue; cultured gingival fibroblasts expressed renin, angiotensinogen and AT1a receptor. IHC demonstrated the existence of renin in vessels of the rat gingival tissue. ACE activity was detected by the fluorimetric assay (4.95±0.89 nmol His-Leu/g.min). When Ang I was used as the substrate, HPLC analyses showed the formation of Ang 1-9 (0.576±0.128 nmol/mg.min), Ang II (0.066±0.008 nmol/mg.min) and Ang 1-7 (0.111±0.017 nmol/mg.min) whereas these same peptides (0.139±0.031; 0.206±0.046 and 0.039±0.007 nmol/mg.min, respectively) and Ang I (0.973±0.139 nmol/mg.min) were formed when TDP was the substrate. Additionally, HPLC revealed absence of Ang II degrading enzymes in rat gingival tissue homogenates. In conclusion, the results presented here clearly show the existence of a local RAS in the rat gingival tissue, which is capable of generating Ang II and other vasoactive peptides in vitro. Further studies are required to elucidate the role of this system in the rat gingival tissue.

Jiang, Lili. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 215-235). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

研究背景和目的 / 高血壓和糖尿病是人群中常見的疾病，兩者常共同存在，其共存的病理生理機制非常複雜，其中腎素血管景張素系統功能紊亂起重要作用。多個研究表明血管緊張素轉化晦抑制劑和血管緊張素II 1 型受體阻滯劑通過調節不同基因的表達，發揮其保護心血管和腎臟功能的效用。然而，目前仍缺乏遠兩類藥物影響全基因表達譜的全面調查。因此，本研究應用全基因表達譜晶片技術，檢測分析了高血壓和糖尿病並發的病人在服用安慰劑、雷米普利(ramipril)和替米沙坦(telmisartan)後的全基因表達譜的變化，從而全面評估了血管緊張素轉化臨抑制劑和血管繁張素II 1 型受體阻滯劑對相關基因的轉錄調控作用。 / 方法 / 11 名患有高血壓和糖尿病的病人(男性5 名)在服用安慰劑最少2 星期后，以隨機吹序接受為期各6 星期的雷米普利和替米沙坦治療，並分別在安慰劑期和2 個藥物治療期結束后提取心A 進行全基因表達譜分析。 / 結果 / 與服用安慰劑時的全基因表達譜相比，雷米普利治療后有267 個基因的表達降低， 99 個基因的表達增強。表達差異幅度為-2.0 至1.3 (P < 0.05) 。表達下降的基因主要與血管平滑肌收縮、炎症反應和氧化壓力相關。表達增強的基因主要與心血管炎症反應負調節相關。基因共表達網絡分析表明， 2 個共表達基因組與雷米普利的降血壓作用相闕， 3 個共表達基因組與肥胖相關。 / 與服用安慰劑時的全基因表達譜相比， 替米拉)、坦治療后有55 個基因表達降低， 158 個基因的表達增強。表達差異幅度為-1. 9 至1.3 (P < 0.05) 。表達增強的基因主要與脂質代謝、糖代謝和抗炎症因子作用相關。基因共表達網絡分析表明， 2 個共表達基因組與替米沙坦對24 小時舒張壓負荷量的作用相關， 2 個共表達基因組則與總膽固醇， 低密度脂蛋白膽固醇和C 反應蛋白相關。 / 結論 / 本論文描述了高血壓和2 型糖尿病病患全基因組表達的總體模式及經藥物治療後表達譜的相應改變， 為今後進一步研究腎素血管緊張素系統抑制劑和高血壓、糖尿病發展進程的相互作用提供了方向。 / Background and aim: Pathophysiological mechanisms underpinning the coexistence of hypertension and type 2 diabetes are complex systemic responses involving dysregulation of the renin-angiotensin system (RAS). We conducted this study to investigate the genome wide gene expression changes in patients with both hypertension and diabetes at three treatment stages, including placebo, ramipril and telmisartan. This study aimed to obtain a panoramic view of interactions between gene transcription and antihypertensive therapy by RAS inhibition. / Methods: 11 diabetic patients (S men) with hypertension were treated with placebo for at least 2 weeks followed by 6 weeks randomised crossover treatment with ramipril Smg daily and telmisartan 40mg daily, respectively. Total RNA were extracted from leukocytes at the end of placebo and each treatment period, and were hybridized to the whole transcript microarray. The limma package for R was used to identify differentially expressed genes between placebo and the 2 active treatments. The weighted gene coexpression network analysis (WGCNA) was applied to identify groups of genes (modules) highly correlated to a common biological function in pathogenesis and progression of hypertension and diabetes. / Results: There were 267 genes down-regulated and 99 genes up-regulated with ramipril. Fold changes of gene expression were ranged from -2.0 to 1.3 (P < 0.05). The down-regulated genes were involved in vascular signalling pathways responsible for vascular smooth muscle contraction, inflammation and oxidative stress. The up-regulated genes were associated with negative regulation of cardiovascular inflammation. The WGCNA identified 17 coexpression gene modules related to ramipril. The midnight blue (57 genes, r < -0.44, P < 0.05) and magenta (190 genes, r < -0.44, P < 0.05) modules were significantly correlated to blood pressure differences between placebo and ramipril. / There were 55 genes down-regulated and 158 genes up-regulated with telmisartan. Fold changes of gene expression were ranged from -1.9 to 1.3 (P < 0.05). The down-regulated genes were mainly associated with cardiovascular inflammation and oxidative stress. The up-regulated genes were associated with lipid and glucose metabolism and anti-inflammatory actions. The WGCNA identified 8 coexpression gene modules related to telmisartan. The black (56 genes, r = 0.46, P = 0.03) and turquoise (1340 genes, r = -0.48, P = 0.02) modules were correlated with diastolic blood pressure load. The blue (1027 genes) module was enriched with genes correlated with total cholesterol (r = - 0.52, P = 0.01), LDL-C (r = - 0.58, P = 0.004), and hsCRP (r = -0.57, P = 0.006). The green module (272 genes) was significantly correlated with LDL-C (r = - 0.44, P = 0.04) and hsCRP (r = - 0.59, P = 0.004). / Conclusion: Genome wide gene expression profiling in this study describes the general pattern and treatment responses in patients with hypertension and type 2 diabetes, which suggests future directions for further investigations on the interaction between actions of the RAS blockers and disease progression. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Deng, Hanbing. / "December 2011." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 198-256). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Declaration --- p.i / Publications --- p.ii / Abstract --- p.iv / 論文摘要 --- p.vi / Acknowledgements --- p.viii / Table of Contents --- p.x / List of tables --- p.xiv / List of figures --- p.xv / List of appendices --- p.xvii / List of abbreviations --- p.xviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Epidemiology --- p.6 / Chapter 1.2.1 --- Epidemiology of hypertension --- p.9 / Chapter 1.2.2 --- Epidemiology of type 2 diabetes --- p.10 / Chapter 1.3 --- Aetiology --- p.13 / Chapter 1.3.1 --- Ageing --- p.13 / Chapter 1.3.1.1 --- Age-induced artery stiffness --- p.14 / Chapter 1.3.1.2 --- Age-related endothelial dysfunction --- p.14 / Chapter 1.3.2 --- The renin-angiotensin system (RAS) --- p.16 / Chapter 1.3.2.1 --- The local RAS --- p.20 / Chapter 1.3.2.2 --- The RAS and insulin resistance --- p.22 / Chapter 1.3.2.3 --- The RAS and inflammation --- p.26 / Chapter 1.3.2.4 --- The RAS and oxidative stress --- p.28 / Chapter 1.3.3 --- Obesity --- p.31 / Chapter 1.3.3.1 --- Obesity and renin-angiotensin system (RAS) --- p.33 / Chapter 1.3.3.2 --- Obesity and insulin resistance --- p.36 / Chapter 1.3.3.3 --- Obesity and oxidative stress --- p.38 / Chapter 1.3.3.4 --- Obesity and sympathetic nervous system (SNS) --- p.38 / Chapter 1.4 --- Pharmacogenomics of antihypertensive therapy --- p.39 / Chapter 1.4.1 --- Angiotensin-converting enzyme inhibitors (ACEIs) --- p.41 / Chapter 1.4.2 --- Angiotensin II type 1 receptor blockers (ARBs) --- p.43 / Chapter Chapter 2 --- Aim --- p.59 / Chapter Chapter 3 --- Methods --- p.60 / Chapter 3.1 --- Subjects --- p.60 / Chapter 3.1.1 --- Subject recruitment protocol --- p.60 / Chapter 3.1.2 --- Definition of type 2 diabetes --- p.62 / Chapter 3.1.3 --- Definition of obesity --- p.62 / Chapter 3.1.4 --- Definition of dyslipidaemia --- p.63 / Chapter 3.2 --- Study design and procedure --- p.64 / Chapter 3.2.1 --- Blood pressure assessments --- p.65 / Chapter 3.2.2 --- Anthropometric measurements --- p.68 / Chapter 3.2.3 --- Medical history, life style and side effect evaluation --- p.68 / Chapter 3.2.4 --- RNA isolation --- p.68 / Chapter 3.2.5 --- RNA quality assessment --- p.70 / Chapter 3.2.6 --- Oligonucleotide microarrays --- p.71 / Chapter 3.2.7 --- DNA extraction --- p.75 / Chapter 3.2.8 --- Biomedical measurements --- p.76 / Chapter 3.2.8.1 --- Glycosylated haemoglobin Alc (HbA₁c) --- p.77 / Chapter 3.2.8.2 --- Fasting plasma glucose (FP G) --- p.77 / Chapter 3.2.8.3 --- Fasting insulin --- p.77 / Chapter 3.2.8.4 --- Plasma urate --- p.77 / Chapter 3.2.8.5 --- High sensitive C-reactive protein (hsCRP) --- p.78 / Chapter 3.2.8.6 --- Fasting plasma triglycerides (TG) --- p.78 / Chapter 3.2.8.7 --- Fasting plasma cholesterols --- p.78 / Chapter 3.2.8.8 --- Renal and liver functions --- p.78 / Chapter 3.2.8.9 --- Urinary parameters --- p.79 / Chapter 3.3 --- Statistical Analysis --- p.79 / Chapter 3.3.1 --- Statistical analysis of clinical and biomedical data --- p.79 / Chapter 3.3.2 --- Analysis of microarray data --- p.80 / Chapter 3.3.2.1 --- Raw data assessment --- p.80 / Chapter 3.3.2.2 --- Data normalisation --- p.92 / Chapter 3.3.2.3 --- Data filtering --- p.96 / Chapter 3.3.2.4 --- Linear models for assessment of differential expression --- p.96 / Chapter 3.3.2.5 --- Weighted gene coexpression network analysis --- p.101 / Chapter 3.3.2.6 --- Network visualisation and gene ontology analysis --- p.102 / Chapter 3.3.3 --- Sample size calculation --- p.103 / Chapter Chapter 4 --- Results --- p.104 / Chapter 4.1 --- Demographic and biomedical characteristics at baseline --- p.104 / Chapter 4.1.1 --- Hypertension and diabetes status at baseline --- p.108 / Chapter 4.1.2 --- Prevalence of dyslipidaemia --- p.108 / Chapter 4.1.3 --- Prevalence of obesity --- p.109 / Chapter 4.1.4 --- Prevalence of metabolic syndrome --- p.109 / Chapter 4.1.5 --- Inflammation markers --- p.110 / Chapter 4.2 --- Blood pressure response to the RAS blockers --- p.110 / Chapter 4.2.1 --- Clinic blood pressure --- p.110 / Chapter 4.2.2 --- 24-hour ambulatory blood pressure --- p.112 / Chapter 4.3 --- Biomedical characteristics --- p.118 / Chapter 4.4 --- Compliance, side effects and adverse events --- p.120 / Chapter 4.5 --- Gene expression differences between treatments --- p.121 / Chapter 4.5.1 --- Gene expression differences between placebo and ramipril --- p.121 / Chapter 4.5.1.1 --- Expression changes in genes related to regulation of transcription with ramipril --- p.122 / Chapter 4.5.1.2 --- Expression changes with ramipril in genes related to molecular mechanism of cardiovascular changes in hypertension --- p.125 / Chapter 4.5.1.3 --- Expression changes in genes related to blood pressure with ramipril --- p.128 / Chapter 4.5.1.4 --- Expression changes in genes related to fatty acid metabolism with ramipril --- p.130 / Chapter 4.5.1.5 --- Expression changes in genes related to inflammation with ramipril --- p.130 / Chapter 4.5.1.6 --- Expression changes in genes related to oxidative stress with ramipril --- p.133 / Chapter 4.5.1.7 --- Power estimation --- p.133 / Chapter 4.5.2 --- Gene expression differences between placebo and telmisartan --- p.135 / Chapter 4.5.2.1 --- Changes in regulation oftranscription with telmisartan --- p.137 / Chapter 4.5.2.2 --- Expression changes in genes related to glucose metabolism with telmisartan --- p.141 / Chapter 4.5.2.3 --- Expression changes in genes related to lipid metabolism with telmisartan --- p.143 / Chapter 4.5.2.4 --- Expression changes in genes related to inflammation with telmisartan --- p.143 / Chapter 4.5.2.5 --- Power estimation --- p.145 / Chapter 4.5.3 --- WGCNA for comparison between placebo and ramipriI --- p.147 / Chapter 4.5.3.1 --- Midnight blue module and clinical responses to ramipril --- p.152 / Chapter 4.5.3.2 --- Magenta module and blood pressure responses to ramipril --- p.154 / Chapter 4.5.3.3 --- Yellow module and clinical responses to ramipril --- p.158 / Chapter 4.5.3.4 --- Red module and clinical responses to ramipril --- p.161 / Chapter 4.5.3.5 --- Salmon module and clinical responses to ramipril --- p.163 / Chapter 4.5.4 --- WGCNA for comparison between placebo and telmisaItan --- p.168 / Chapter 4.5.4.1 --- Diastolic blood pressure load and gene coexpression modules --- p.168 / Chapter 4.5.4.2 --- Lipids, hsCRP and gene coexpression modules --- p.172 / Chapter Chapter 5 --- Discussion --- p.176 / Chapter 5.1 --- Gene expression changes related to ramipril --- p.177 / Chapter 5.1.1 --- Gene expression changes and blood pressure reduction by ramipri1 --- p.177 / Chapter 5.1.2 --- Gene expression changes and vascular protection by ramipri1 --- p.181 / Chapter 5.1.3 --- Obesity and gene expression changes by ramipril --- p.183 / Chapter 5.2 --- Gene expression changes related to telmisartan --- p.185 / Chapter 5.2.1 --- Blood pressure and coexpressed gene modules with telmisartan --- p.185 / Chapter 5.2.2 --- Lipid metabolism and gene expression changes by telmisartan --- p.187 / Chapter 5.2.3 --- Glucose metabolism and gene expression changes by telmisartan --- p.189 / Chapter 5.2.4 --- hsCRP and gene expression changes by telmisartan --- p.190 / Chapter 5.3 --- Limitations of this study and future directions of research --- p.191 / Chapter Chapter 6 --- Conclusion --- p.194 / References --- p.198 / Appendices --- p.257

Chronic treatment with enalapril and valsartan significantly improved endothelium-dependent relaxations of aortas from ovariectomized rats. The present results clearly point to that chronic treatment with enalapril or valsartan reduced expression and function of RAS and associated oxidative stress, thereby augmented NO bioavailability and improved endothelium-dependent relaxations. These results provided novel evidence supporting a potential application of ACEI and ARB in the treatment of endothelial dysfunction-associated vascular complications in postmenopausal women. / Functional studies showed that acetylcholine-induced relaxations in isolated aortas were impaired in a time-dependent manner, from the 4th-week to the 12th-week after ovariectomy. The impaired relaxations were partially restored by acute treatment with losartan [angiotensin II type 1 receptor (AT1R) blocker] and apocynin [NAD(P)H oxidase inhibitor]. The present results demonstrate that estrogen deficiency blunted endothelium-dependent relaxations due to impaired the NO bioavailability, which is closely associated with the reduced eNOS activity and elevated RAS expression and associated NAD(P)H oxidase-mediated oxidative stress in the vascular wall. / The present study shows that chronic consumption of cranberry juice restored the endothelium-dependent relaxations in aortas from ovariectomized rats. In ovariectomized rats, the phenylephrine-induced a higher active vascular tension; which was prevented by chronic consumption of cranberry juice. The present data also shows that cranberry juice administration significantly reduces the elevated serum levels of total cholesterol, triglyceride, high density lipoprotein (HDL) cholesterol, non-HDL (nHDL) cholesterol, and nHDL/HDL. The active ingredients in the cranberry juice organic extract accounting for the vascular benefit remain to be further examined even though the extract causes endothelial NO-dependent relaxations in normal rat aortas and contains several bioactive compounds, some of which may protect the vascular function. This study provides the first line of evidence concerning a significant vascular benefit of chronic consumption of cranberry juice during estrogen deficiency. (Abstract shortened by UMI.) / The present study used ovariectomized female rats that mimic the "equivalent" state of menopause in human and investigated whether dysregulation of RAS components contribute to endothelial dysfunction and whether chronic treatment with ACEI (enalapril) or ARB (valsartan) could restore endothelial function in ovariectomized rats. / The second objective of the present study was to investigate whether or not consumption of cranberry juice, a popular drink in Western countries, could restore endothelial function during estrogen deficiency and to elucidate the cellular mechanisms underlying the improved endothelial function. / Yung, Lai Ming. / Adviser: Huana Yu. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3252. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 148-168). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

In the first study, I aimed to compare the angiotensin II type 1 receptor (AT1R) expression levels of the isolated pancreatic islets from normal and mouse model of T2DM. In addition, 4-week-old diabetic mice were orally treated with AT1R antagonist losartan for 8 weeks. It is found that AT1R mRNA was upregulated markedly in diabetic islets and double-immunolabeling confirmed that AT1R was localized to beta-cells. Losartan selectively improved glucose-induced insulin release and (pro)insulin biosynthesis in diabetic islets. Oral losartan treatment delayed the onset of diabetes, and reduced hyperglycemia and glucose intolerance in diabetic mice. These data indicate that AT1R antagonism improves beta-cell function and glucose tolerance in young T2DM mice. / In the second study, I aimed to examine how the upregulated RAS could impair beta-cell function, where oxidative stress is the potential mediator. Meanwhile, T2DM results in oxidative stress-mediated activation of uncoupling protein 2 (UCP2), a negative regulator of islet function. Thus, it was postulated that some of the protective effects of AT1R antagonism might be mediated through interference with this pathway and tested this hypothesis in a mouse model of T2DM. In order to achieve this, losartan was given to 4-week-old diabetic mice for 8 weeks. UCP2-driven oxidative damage and apoptosis were analyzed in isolated islets. Results showed that losartan selectively inhibited oxidative stress via NADPH oxidase downregulation; this in turn suppressed UCP2 expression, thus improving beta-cell insulin secretion while decreasing apoptosis-induced beta-cell mass loss in diabetic mice islets. These data indicate that islet AT1R activation in young diabetic mice can lead to progressive islet beta-cell failure through UCP2-driven oxidative damage and apoptosis. / The mechanisms by which chronic hyperglycemia associated with glucotoxicity causes beta-cell dysfunction and apoptosis remain ambiguous. Voltage-gated outward potassium (Kv) current, which mediates beta-cell membrane potential and limits insulin secretion, could play a role in glucotoxicity. Meanwhile the RAS has been shown to be upregulated by prolonged exposure to high glucose. In the third part of my study, I therefore investigated the effects of prolonged exposure to high glucose and angiotensin II (Ang II) on the expression and activity of Kv channels in mouse pancreatic beta-cell. Dissociated mice beta-cells, incubated in 5.6 mM or 28 mM glucose for 3-5 days, were used for electrophysiological study; while isolated islets cultured for 1-7 days were proceeded for gene/protein expression analysis. Both Kv channel expression and current were markedly increased by prolonged glucose incubation. Simultaneously, Ang II reduced Kv current under normal glucose condition, while high glucose incubation abolished the effect of Ang II. Moreover, the ability of Ang II on Kv current reduction was eliminated by inhibiting AT2R but not AT1R. These data indicated that Ang II reduced Kv current via AT2R, which was abolished by prolonged high glucose incubation. On the other hand, high glucose increased Kv channel expression and current, which might alter the ability of insulin secretion in beta-cell. (Abstract shortened by UMI.) / Chu, Kwan Yi. / Adviser: P. S. Leung. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3246. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 163-188). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Diabetic nephropathy (DN) is one of the leading causes of end stage renal disease (ESRD) in western world and has a trend to spread in developing countries. Pathogenesis of DN is not fully elucidated. Studies of recent years showed that podocyte loss and activation of the rennin-angiotensin system (RAS), especially intra-renal RAS, played important roles in this process. Although renal biopsy is currently the most common way used to determine the expression pattern of podocyte and RAS associated molecules in DN, this invasive procedure has its own risk and is not practical for serial monitoring. We hypothesized that measurement of messenger ribonucleic acid (mRNA) expression of related genes in the urinary sediment might be a useful way to assess the severity of DN. / Firstly, we found that urinary mRNA expressions of podocyte-associated molecules nephrin, podocin, synaptopodin, Wilm's tumor-1 (WT-1) and alpha-actinin-4 were higher in patients with DN than in healthy controls, and urinary nephrin, podocin and synaptopodin expression was related to proteinuria and baseline renal function. In addition, there was a close relationship between urinary mRNA expression of type 2 angiotensin converting enzyme (ACE2), a key element of RAS, and the degrees of proteinuria, renal function and rate of decline of glomerular filtration rate (GFR). Urinary mRNA expression of ACE also inversely correlated with the rate of renal function decline. / In the next step, we studied the change in urinary mRNA expression of nephrin, podocin, synaptopodin, ACE and ACE2 in patients with DN treated with angiotensin converting enzyme inhibitor (ACEI) and addition of angiotensin receptor blocker (ARB). We found that urinary mRNA expression of podocin, synaptopodin and propably nephrin increased with disease progression, and percentage change in urinary podocin expression negatively correlated with rate of decline of GFR. Furthermore, serial measurement of urinary expression of nephrin and possibly synaptopodin may reflect therapeutic response to ARB in these patients. Urinary mRNA expression of ACE and ACE2, however, remained unchanged during the study duration and did not correlate with therapeutic response. / In this series of work, we investigated (i) the relation between the gene expression profile of podocyte-associated molecules and RAS related molecules in the urinary sediment and the severity of DN, including clinically defined parameter of disease severity, histological scarring, and the degree of intra-renal podocyte loss, (ii) the relation between urinary and intra-renal gene expression of patients with DN, (iii) the application of urinary gene expression on the monitoring of disease progression and therapy response of DN. The urinary mRNA expression of related genes was quantified by real-time quantitative polymerase chain reaction (RT Q-PCR). The intra-renal mRNA expression of related genes was studied from the histologic specimens of kidney biopsy by laser catapult microdissection (LCM) and RT Q-PCR. The degree of renal scarring was determined by morphometric analysis. Glomerular podocyte number was determined by stereological study on serial sections of renal biopsy specimen. / Taken together, our results suggest that although urinary mRNA expression of podocyte and RAS associated molecules is not related to intra-renal expression, urinary expression has the potential to be used as a non-invasive tool to assess the severity and progression of DN, and serial measurements of urinary gene expression of podocyte associated molecules may be used to reflect therapy response for patients with DN. Our findings also indicate that the information from urinary gene expression is supplementary to, but not a surrogate of, the data obtained from renal biopsy. / We then examined the relation between urinary gene expression and histological changes in the kidney. We found that urinary WT-1 expression correlated with the degree of kidney fibrosis. Unlike intra-renal expression, urinary mRNA expression of podocyte associated molecules did not correlate with glomerular podocyte number. There was also no association between urinary and intra-renal mRNA expression. / Wang, Gang. / Adviser: Cheuk Chen Szeto. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3423. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 156-180). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

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