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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiotensin (Ang) II plays a pivotal role in vascular fibrosis, which leads to serious complications in hypertension and diabetes. Connective tissue growth factor (CTGF) is a potent profibrotic factor implicated in the Ang II-induced pathologic fibrosis process. PPAR-gamma activators thiazolidinediones have been recently reported to have beneficial vascular effects. However, their effects and related molecular mechanisms on extracellular matrix (ECM) turnover in vascular smooth muscle cells (VSMCs) are unknown. The present study evaluated the regulation of Ang II-induced CTGF, ECM production and cell growth by rosiglitazone in VSMCs. In aorta of Ang II-infused rats, CTGF expression was markedly increased, and type III collagen and fibronectin overexpression was observed. Cotreatment with rosiglitazone diminished these changes, whereas increased nuclear PPAR-gamma expression in VSMCs. In growth-arrested VSMCs, rosiglitazone attenuated the proliferation and apoptosis, increased PPAR-gamma production and activation, and reduced CTGF and ECM production in response to Ang II in a dose-dependent fashion. These inhibitory effects were attenuated by the pretreatment of cells with PPAR-gamma antagonist GW9662 or bisphenol A diglycidyl ether (BADGE). Furthermore, rosiglitazone inhibited Ang II-induced Smad2 production and phosphorylation but had no effect on transforming growth factor-beta(1) (TGF-beta(1)) expression. These results suggest that in Ang II-stimulated VSMCs, rosiglitazone caused an antiproliferative, antiapototic effect and reduces ECM production through mechanisms that include reducing CTGF expression, and a crosstalk between PPAR-gamma and Smad may be involved in the inhibitory effects of rosiglitazone. This novel finding suggests a role of PPAR-gamma activators in preventing Ang II-induced vascular fibrosis.
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PMID:Rosiglitazone inhibits angiotensin II-induced CTGF expression in vascular smooth muscle cells - role of PPAR-gamma in vascular fibrosis. 1707 4

Peroxisome Proliferator-Activate Receptors (PPARs) are transcription factors belonging to the nuclear receptor superfamily. The three PPARs (alpha, beta/delta, and gamma) are distributed differently in the different organs. PPARalpha is most common in the liver, but also found in kidney, gut, skeletal muscle and adipose tissue, while PPARbeta/delta, is fairly ubiquitous; it may be found in body tissues and brain (for myelination process and lipid metabolism in the brain). PPARgamma has 3 isoforms, such as PPARgamma 1, PPARgamma 2, and PPARgamma 3. The syndrome-X was firstly coined by Reaven in 1988 and then to be provided in 1999 by the name : the metabolic syndrome-X. This metabolic syndrome represents a "Cluster" of metabolic disorders and cardiovascular risk factors which has been collected and summarized by the author and such a cluster includes: insulin resistance/hyperinsulinemia, central obesity, glucose intolerance/DM, atherogenic dyslipidemia (increase TG, decrease HDL-cholesterol, increase Apo-B, increase small dense LDL), hypertension, prothrombotic state (increase PAI-1, increase F-VII, increase fibrinogen, increase vWF, increase adhesion molecules), endothelial dysfunction, hyperuricemia, and increased hsC-RP and cytokines. The metabolic syndrome-X may lead to the development of T2DM and coronary heart disease (CHD); insulin resistance plays pivotal roles in the progression of such a syndrome and cardiovascular diseases. Improvement of Insulin Resistance, therefore, is most likely to reduce the high cardiovascular event rate in T2DM. It has been generally accepted that Insulin Resistance (detected by HOMA-R) and Acute Insulin Response = AIR (by HOMA-B) are both usually present in T2DM. The Thiazolidinedions (TZDs) are Insulin Sensitizers (e.g Rosiglitazone = ROS, Pioglitazone = PIO) introduced into clinical practice in 1997; clinical evidence data showed that TZDs improved both HOMA-R, and HOMA-B. PPARgamma can be activated by TZDs and it appears to be fundamental to the pathophysiology of diabetes mellitus i.e increase GLUT-4, increase glucokinase, decrease PEPCK, increase GLUT-4, and decreases production by fat cell of several mediators that may cause insulin resistance, such as TNFalpha and resistin. PPARgamma also mediates increased production of Adiponectin and the insulin signaling intermediate PI3K, and both actions lead to increase insulin sensitivity. A "dual PPARgamma-PPARalpha agonists" (e.g PIO, but ROS poorly activate PPARalpha) might lower glucose and modulate lipids. Thus, PIO, as a stronger "dual PPARgamma-PPARalpha agonists", shows an important therapeutic pathway in diabetes mellitus and cardiovascular diseases, even in metabolic syndrome. Current evidence suggests a close relationship between activation of PPARgamma and restoration of insulin sensitivity by reductions in TNFalpha and FFAs, and the enhancement of insulin stimulation of PI3-K Pathway and also increase adiponectin & decrease resistin.
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PMID:New approach in the treatment of T2DM and metabolic syndrome (focus on a novel insulin sensitizer). 1711 68

Telmisartan, a new angiotensin II type 1 receptor blocker (ARB), was recently reported to stimulate PPARgamma, and stronger effects of Telmisartan on insulin sensitivity has been expected than the class effect of ARB. In the present study, we examined the effects of Telmisartan on insulin sensitivity and adipokine levels in hypertensive and type 2 diabetic patients. Outpatients with both hypertension and type 2 diabetes mellitus (n=36; male 23, female 13), received 20-40mg Telmisartan orally once daily for 6 months. Physical examinations and blood or urine tests were performed before and 3 or 6 months after starting Telmisartan treatment. Results were statistically compared using Wilcoxon analysis. Telmisartan treatment for 3 or 6 months reduced systolic and diastolic blood pressure and urinary albumin excretion. Fasting plasma glucose, HbA1c, total and HDL-cholesterol, triglyceride, body weight, BMI and waist length were not changed. Fasting IRI and HOMA-IR were significantly decreased after Telmisartan treatment, suggesting the improved insulin sensitivity. Total and high molecular adiponectin were not changed. Interestingly, serum leptin was significantly increased by 3 months Telmisartan treatment, suggesting a possible involvement of leptin in improved insulin sensitivity. In conclusion, Telmisartan improved insulin resistance with increased serum leptin level in hypertensive and type 2 diabetic patients.
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PMID:Telmisartan reduced blood pressure and HOMA-IR with increasing plasma leptin level in hypertensive and type 2 diabetic patients. 1724 Apr 72

The prevalence of obesity has been increasing dramatically in the last decades in the whole world, not only in industrialized countries but also in developing areas. A major complication of obesity is insulin resistance and type 2 diabetes. Diabetes is also rapidly increasing world-wide--reaching a prevalence in adults of approx. 5-6% in Central Europe and in the US, and more than 50% in specific, genetically prone populations. This article reviews pathogenetic mechanisms linking obesity and type 2 diabetes. Emphasis is placed on the observation that excessive amounts of adipocytes are associated with an impairment of insulin sensitivity, a key feature of the "metabolic syndrome". This is a cluster of metabolic abnormalities such as type 2 diabetes, hypertension and dyslipidemia; all of them are enhanced by the presence of visceral (abdominal) obesity and all contribute to the increased cardiovascular risk observed in these patients. Besides release of free fatty acids, adipocytes secrete substances that contribute to peripheral insulin resistance, including adiponectin, resistin, TNF-alpha and interleukin 6. Increased turnover of free fatty acids interferes with intracellular metabolism of glucose in the muscle, and they exert lipotoxic effect on pancreatic beta-cells. The pre-receptor metabolism of cortisol is enhanced in visceral adipose tissue by activation of 11 beta-hydroxysteroid dehydrogenase type 1. A new class of anti-diabetic drugs (thiazolidinediones, or glitazones) bind to peroxisome proliferator activated receptor (PPAR-gamma) and lower thereby plasma free fatty acids and cytokine production in adipocytes, in addition to a decrease of resistin and an increase in adiponectin observed in animals, resulting in an overall increase in insulin sensitivity and in an improvement of glucose homeostasis. However, the first step to avoid insulin resistance and prevent the development of diabetes should be a reduction in body weight in overweight subjects, and an increase in physical activity. There are now three published randomized controlled trials demonstrating that in high risk individuals, life style changes with modest weight lost, associated with diminished fat intake and an increase in fruit and vegetable consumption result in marked inhibition of the transition from the prediabetic state to manifest type 2 diabetes.
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PMID:From obesity to diabetes. 1724 79

Obesity, hypertension, dyslipidemia and glucose intolerance cluster in the insulin resistance syndrome. Angiotensin II receptor blockers (ARB) are able to reduce insulin resistance. Furthermore, among ARB, telmisartan displays the property of stimulating PPARgamma. The aim of the study was to examine if and to what extent treatment with irbesartan and telmisartan induces variations in metabolic parameters in insulin resistant, hypertensive subjects. Forty-six non diabetic, obese, insulin-resistant, hypertensive patients took part in the study. They were divided into 2 groups. Group A (23) was submitted to irbesartan 150 mg/day, Group B (23) to telmisartan 80 mg/day for 6 months. Adiponectin, glucose, cholesterol, triglycerides, free fatty acids (FFA), steady-state plasma insulin and glucose (SSPG), 24-hBP were determined at the beginning and at the end of the study. Both irbesartan or telmisartan reduced blood pressure and ameliorated the insulin sensitivity, with increased adiponectin values; in Group B, the amelioration of metabolic parameters was greater than in Group A and the reduction of blood pressure was related with variation of adiponectin levels. Data obtained showed that the antihypertensive action of telmisartan and irbesartan is associated with the amelioration of the metabolic picture. The greater impact on the improvement of the metabolic profile showed by telmisartan and the inverse correlation between adiponectin levels and blood pressure may be partly due to the action as partial PPARgamma agonist displayed by telmisartan.
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PMID:The effects of irbesartan and telmisartan on metabolic parameters and blood pressure in obese, insulin resistant, hypertensive patients. 1725 91

Inhibition of the renin-angiotensin system reportedly exerts potent antiatherogenic effects by reducing vascular inflammation. We tested the hypothesis that pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, further reduces vascular inflammation in patients receiving angiotensin II receptor blockers. Patients with hypertension who had developed type 2 diabetes mellitus were randomly assigned to receive either pioglitazone (15 mg/d, n = 20) or voglibose, an alpha-glucosidase inhibitor (0.6 mg/d, n=19) for 6 months, and changes in their serum concentrations of C-reactive protein (CRP), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were monitored. Pioglitazone, but not voglibose, reduced CRP levels within 1 month (-51%+/-7%, mean+/-SEM; P<.001). C-reactive protein levels were decreased after 6 months of treatment with either pioglitazone or voglibose, with the former being more effective (-57%+/-8% vs -9%+/-18%; P<.05). The levels of ICAM-1 and VCAM-1 were significantly reduced after 1 month of pioglitazone therapy (-9%+/-3% and -8%+/-3%, respectively; both P<.05), with the beneficial effects persisting throughout the study period. In contrast, the levels of ICAM-1 and VCAM-1 were not altered during the study period in patients on voglibose. There was no correlation between the reduction of hemoglobin A1c and that of CRP, ICAM-1, or VCAM-1. These results suggest that augmentation with pioglitazone further reduces vascular inflammation in patients with hypertension and diabetes who are receiving angiotensin II receptor blockers. This may contribute to the reduction of cardiovascular events in this at-risk population.
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PMID:Pioglitazone produces rapid and persistent reduction of vascular inflammation in patients with hypertension and type 2 diabetes mellitus who are receiving angiotensin II receptor blockers. 1737 17

At a time when the twin epidemics of obesity and type 2 diabetes threaten to engulf even the most well-resourced Western healthcare systems, the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) has emerged as a bona fide therapeutic target for treating human metabolic disease. The novel insulin-sensitizing antidiabetic thiazolidinediones (TZDs, e.g., rosiglitazone, pioglitazone), which are licensed for use in the treatment of type 2 diabetes, are high-affinity PPARgamma ligands, whose beneficial effects extend beyond improvement in glycaemic control to include amelioration of dyslipidaemia, lowering of blood pressure, and favourable modulation of macrophage lipid handling and inflammatory responses. However, a major drawback to the clinical use of exisiting TZDs is weight gain, reflecting both enhanced adipogenesis and fluid retention, neither of which is desirable in a population that is already overweight and prone to cardiovascular disease. Accordingly, the "search is on" to identify the next generation of PPARgamma modulators that will promote maximal clinical benefit by targeting specific facets of the metabolic syndrome (glucose intolerance/diabetes, dyslipidaemia, and hypertension), while simultaneously avoiding undesirable side effects of PPARgamma activation (e.g., weight gain). This paper outlines the important clinical and laboratory observations made in human subjects harboring genetic variations in PPARgamma that support such a therapeutic strategy.
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PMID:'Striking the Right Balance' in Targeting PPARgamma in the Metabolic Syndrome: Novel Insights from Human Genetic Studies. 1738 71

Angiotensin II exerts its central nervous system effects primarily via its receptors AT1 and AT2, and it participates in the pathogenesis of ischemia via AT1. The selective AT1 receptor blocker (ARB) is used in the hypertension treatment, and it exerts a variety of pleiotropic effects, including antioxidative, antiapoptotic, and anti-inflammatory effects. In this study, we investigated the therapeutic effect of the ARB telmisartan in experimental intracerebral hemorrhage (ICH) in normotensive rats. ICH was induced via the collagenase infusion or autologous blood injection. Either telmisartan at 30 mg/kg/dose or phosphate-buffered saline was orally administered 2 h after ICH induction. We evaluated hemorrhage volume, brain water content, and functional recovery, and we performed the histological analysis for terminal deoxynucleotidyl transferase dUTP nick-end labeling, leukocyte infiltration, and microglia activation. A variety of intracellular signals, in terms of oxidative stress, apoptotic molecules, and inflammatory mediators, were also measured. Telmisartan reduced hemorrhage volume, brain edema, and inflammatory or apoptotic cells in the perihematomal area. Telmisartan was noted to induce the expression of endothelial nitric-oxide synthase and peroxisome proliferator-activated receptor gamma and decrease oxidative stress, apoptotic signal, tumor necrosis factor-alpha, and cyclooxygenase-2 expression. The telmisartan-treated rats exhibited less pronounced neurological deficits and recovered better. Thus, telmisartan seems to offer neural protection, including antiapoptosis, anti-inflammatory, and antioxidant benefits in the intracerebral hemorrhage rat model.
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PMID:Blockade of AT1 receptor reduces apoptosis, inflammation, and oxidative stress in normotensive rats with intracerebral hemorrhage. 1753 8

Telmisartan, a highly selective angiotensin-II-receptor antagonist, used for the treatment of hypertension, acts as a partial agonist of the PPAR-gamma (peroxisome proliferator-activated receptor-gamma) receptor, which is involved in the regulation of glucose and lipid metabolism. In the present study the effect of Telmisartan on hypertension, parameters of glucose and lipid metabolism was investigated in 670 patients with the metabolic syndrome. There was a significant (p < 0,05) improvement regarding all parameters involved in the diagnosis of the metabolic syndrome, namely hypertension (systolic: 161,7 +/- 16,3 vs. 136,7 +/- 11,7 mmHg, diastolic: 93,3 +/- 10,1 vs. 80,7 +/- 10,5 mmHg), fasting blood glucose (133,2 +/- 44,1 vs. 116,0 +/- 31,5 mg/dl), triglycerides (227,2 +/- 170,1 vs. 187,8 +/- 94,8 mg/dl), HDL-cholesterin (women: 48,9 +/- 13,1 vs. 51,8 +/- 12,9 mg/dl) and abdominal circumference (women: 101,2 +/- 12,4 vs. 99,3 +/- 12,9 mg/dl, men: 111,9 +/- 14,7 vs. 109,5 +/- 14,4 mg/dl). The number of patients diagnosed with the metabolic syndrome was significantly reduced over the 3 months study duration (38%). The medication was well tolerated and adverse effects were minimal. Thus, Telmisartan can be regarded as an appropriate medication for the therapy of hypertension in patients with the metabolic syndrome with possible additive effects on parameters of glucose and lipid metabolism.
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PMID:[Antihypertensive and metabolic effects of telmisartan in patients with the metabolic syndrome in primary care--a field study]. 1756 69

Peroxisome proliferator-activated receptor (PPAR)-gamma, a target in the treatment of diabetes, improves insulin sensitivity and exerts cardiovascular protective effects by mechanisms that are not completely elucidated. To investigate underlying molecular mechanisms responsible for PPAR-gamma-associated vascular insulin signaling in hypertension, we tested whether PPAR-gamma downregulation in vascular smooth muscle cells (VSMC) from WKY and SHRSP rats would decrease insulin signaling and glucose uptake and whether this response would be worsened by hyperglycemia to a greater extent in VSMC of hypertensive origin. Passaged mesenteric artery VSMC grown in euglycemic (5.5 mmol/L) or hyperglycemic media (25.0 mmol/L) were treated with PPAR-gamma-siRNA (5 nmol/L), PPAR-gamma antagonist (GW-9662, 10 micromol/L), or PPAR-gamma activator (rosiglitazone, 10 micromol/L) in the presence or absence of insulin (100 nmol/L). Immunoblotting revealed that hyperglycemia and PPAR-gamma inhibition significantly (P < 0.001) decreased insulin-stimulated insulin receptor (IR)-beta, Akt, and glycogen synthase kinase (GSK)-3beta phosphorylation, whereas phosphotyrosine phosphatase (PTP)-1B expression was increased in VSMC from both strains. These effects were more pronounced in SHRSP under hyperglycemia. Rosiglitazone tended to increase insulin-mediated IR-beta, Akt, and GSK-3beta phosphorylation in VSMC from both strains, whereas insulin-induced PTP-1B expression was reduced by hyperglycemia. Insulin-stimulated GLUT-4 expression and glucose transport were attenuated by hyperglycemia in both VSMC. These data suggest that PPAR-gamma inhibition results in decreased insulin signaling, particularly in SHR, in an IR-beta phosphorylation-dependent manner.
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PMID:Effects of PPAR-gamma knock-down and hyperglycemia on insulin signaling in vascular smooth muscle cells from hypertensive rats. 1757 98


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