Evidence for the lack of serotonergic mechanism in the regulation of blood-brain barrier.
Ang II-induced systemic and regional haemodynamic effects in normotensive Wistar rats are mediated exclusively via angiotensin II type 1 receptors. No evidence for angiotensin II type 2 receptor-mediated vasoactive responses was obtained.
To investigate the mechanism of Ca(2+)-independent pathways mediated by Rho-kinase in contraction of hepatic stellate cells (HSCs) induced by angiotonin II (Ang II).
A PubMed/MEDLINE search of English-language articles (1990 to September 2005) was used to identify articles describing clinical studies, particularly outcome trials, or mechanisms of therapeutic action pertinent to the therapy of cardiovascular disease or nephropathy.
Stimulation of HSC by Ang II and Aldo results in activation of AP-1 via ERK1/2 pathway leading to up-regulation of AP-1 target gene alpha1 (I) procollagen mRNA expression.
Data from studies of angiotensin-converting enzyme inhibitors provide evidence that the renin-angiotensin-aldosterone system plays a role as a mediator of atrial remodeling in atrial fibrillation. The present study has evaluated the effect of treatment with the angiotensin I type 1 receptor blocker irbesartan on maintaining sinus rhythm after conversion from persistent atrial fibrillation.
Individuals with type 2 diabetes and nephropathy represent a particularly high-risk group for both adverse cardiac as well as renal events. Using the Irbesartan in Diabetic Nephropathy Trial (IDNT) cohort, our objective was to determine baseline characteristics of individuals with type 2 diabetic nephropathy and hypertension predictive for cardiac events. IDNT identified 1715 individuals with type 2 diabetic nephropathy and hypertension having serum creatinine of 1.0 to 3.0 mg/dL and urinary albumin excretion rates > or = 900 mg/day. A cardiovascular (CV) composite was used consisting of CV death, nonfatal MI, hospitalization for heart failure, stroke, amputation, and coronary and peripheral revascularization. Using multivariable Cox regression analysis, 41 baseline characteristics determined a priori were analyzed for their potential relationship to risk of experiencing a CV event. Of the 1715 individuals, 518 (30.2%) had at least one of the CV composite end points. Older age, male gender, longer duration of diabetes, history of cardiovascular disease, history of CHF, high urinary albumin:creatinine ratio, and low serum albumin were strong predictors for CV events; of these, prior history of CVD (RR 2.00, 95% CI 1.63-2.45; P < 0.0001) and high urinary albumin:creatinine ratio (RR 1.29 per natural log unit, 95% CI 1.13-1.48; P = 0.0002) at baseline were highly predictive for cardiovascular events. In conclusion, among individuals with hypertension and diabetic nephropathy, both the degree of albuminuria and lower serum albumin levels provide additional prognostic information concerning cardiovascular risk, in addition to traditional coronary risk factors.
The renin-angiotensin system plays an important role in cardiovascular homeostasis by contributing to the regulation of blood volume, blood pressure, and vascular tone. Because AT(1) receptors have been described in the coronary microcirculation, we investigated whether ANG II contributes to the regulation of coronary vascular tone and whether its contribution is altered during exercise. Since the renin-angiotensin system is activated after myocardial infarction, resulting in an increase in circulating ANG II, we also investigated whether the contribution of ANG II to the regulation of vasomotor tone is altered after infarction. Twenty-six chronically instrumented swine were studied at rest and while running on a treadmill at 1-4 km/h. In 13 swine, myocardial infarction was induced by ligation of the left circumflex coronary artery. Blockade of AT(1) receptors (irbesartan, 1 mg/kg iv) had no effect on myocardial O(2) consumption but resulted in an increase in coronary venous O(2) tension and saturation both at rest and during exercise, reflecting coronary vasodilation. Despite increased plasma levels of ANG II after infarction and maintained coronary arteriolar AT(1) receptor levels, the vasodilation evoked by irbesartan was significantly reduced both at rest and during exercise. In conclusion, despite elevated plasma levels, the vasoconstrictor influence of ANG II on the coronary circulation in vivo is reduced after myocardial infarction. This reduction in ANG II-induced coronary vasoconstriction may serve to maintain perfusion of the remodeled myocardium.
To evaluate the impact of felodipine with irbesartan on sexual function compared with felodipine with metoprolol in hypertensive women.
The aim of this study was to compare the concentration of osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL), and osteopontin (OPN) in stable (asymptomatic) and unstable (symptomatic) carotid atherosclerosis. In addition, we were interested in the effect of angiotensin II blockade on the secretion of these proteins by unstable atherosclerosis.