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Circelli M, Nicolini G, Egan CG, Cremonesi G. Efficacy and safety of delapril/indapamide compared to different ACE-inhibitor/hydrochlorothiazide combinations: a meta-analysis. Int J Gen Med 2012; 5:725-34. [PMID: 23049265 PMCID: PMC3459665 DOI: 10.2147/ijgm.s35220] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The main objective of this meta-analysis was to compare the efficacy of the combination of delapril and indapamide (D+I) to different angiotensin-converting enzyme inhibitor (ACEi) plus hydrochlorothiazide (HCTZ) combinations for the treatment of mild-to-moderate hypertension. A secondary objective was to examine the safety of these two combinations. Studies comparing the efficacy of D+I to ACEi+HCTZ combinations in hypertensive patients and published on computerized databases (1974–2010) were considered. Endpoints included percentage of normalized patients, of responders, change in diastolic and systolic blood pressure (DBP/SBP) at different time-points, percentage of adverse events (AEs), and percentage of withdrawal. Four head-to-head randomized controlled trials (D+I-treated, n = 643; ACEi+HCTZ-treated, n = 629) were included. Meta-analysis indicated that D+I-treated patients had a higher proportion with normalized blood pressure (P = 0.024) or responders (P = 0.002) compared to ACEi+HCTZ-treated patients. No difference was observed between treatments on absolute values of DBP and SBP at different time-points. Although the rate of patients reporting at least one AE was similar in both groups (10.4% versus 9.9%), events leading to study withdrawal were lower in the D+I group versus the ACEi+HCTZ group (2.3% versus 4.8%, respectively; P = 0.018). This meta-analysis suggests that treatment with D+I could provide a higher proportion of normalized or responder patients with good tolerability compared to ACEi+HCTZ combinations.
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Abstract
This article outlines the link between the renin angiotensin aldosterone system (RAAS) and various forms of cardiomyopathy, and also reviews the understanding of the effectiveness of RAAS intervention in this phase of ventricular dysfunction. The authors focus their discussion predominantly on patients who have had previous myocardial infarction or those who have left ventricular hypertrophy and also briefly discuss the role of RAAS activation and intervention in patients with alcoholic cardiomyopathy.
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Affiliation(s)
- Patrick Collier
- Heart Failure Unit, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland
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Measuring and targeting aldosterone and renin in atherosclerosis-a review of clinical data. Am Heart J 2011; 162:585-96. [PMID: 21982648 DOI: 10.1016/j.ahj.2011.06.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 06/21/2011] [Indexed: 01/13/2023]
Abstract
Our understanding of the development and progression of atherosclerosis has increased substantially over the past decades. A significant role for the renin-angiotensin-aldosterone system (RAAS) in this process has gained appreciation in recent years. Preclinical and clinical studies have associated components of the RAAS with various cardiovascular disease conditions. Classically known for its contribution to hypertension, dysregulation of the system is now also believed to promote vascular inflammation, fibrosis, remodeling, and endothelial dysfunction, all intimately related to atherosclerosis. The reduction in cardiovascular mortality and morbidity, as seen with the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, supports the concept that RAAS is involved in the pathogenesis of atherosclerotic disease. However, the underlying molecular mechanisms of the pathophysiology remain to be completely understood. Evidence points toward additional benefit from therapeutic approaches aiming at more complete inhibition of the system and the possible utility of renin or aldosterone in the prediction of cardiovascular outcome. This review will summarize the current knowledge from clinical studies regarding the presumptive role of renin and aldosterone in the prediction and management of patients with atherosclerosis. For this purpose, a literature search was performed, focusing on available clinical data regarding renin or aldosterone and cardiovascular outcome.
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Differential expression of protein kinase C isoforms in coronary arteries of diabetic mice lacking the G-protein Gα11. Cardiovasc Diabetol 2010; 9:93. [PMID: 21190563 PMCID: PMC3024287 DOI: 10.1186/1475-2840-9-93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 12/29/2010] [Indexed: 01/28/2023] Open
Abstract
Background Diabetes mellitus counts as a major risk factor for developing atherosclerosis. The activation of protein kinase C (PKC) is commonly known to take a pivotal part in the pathogenesis of atherosclerosis, though the influence of specific PKC isozymes remains unclear. There is evidence from large clinical trials suggesting excessive neurohumoral stimulation, amongst other pathways leading to PKC activation, as a central mechanism in the pathogenesis of diabetic heart disease. The present study was therefore designed to determine the role of Gq-protein signalling via Gα11 in diabetes for the expression of PKC isozymes in the coronary vessels. Methods The role of Gα11 in diabetes was examined in knockout mice with global deletion of Gα11 compared to wildtype controls. An experimental type 1-diabetes was induced in both groups by injection of streptozotocin. Expression and localization of the PKC isozymes α, βII, δ, ε, and ζ was examined by quantitative immunohistochemistry. Results 8 weeks after induction of diabetes a diminished expression of PKC ε was observed in wildtype animals. This alteration was not seen in Gα11 knockout animals, however, these mice showed a diminished expression of PKCζ. Direct comparison of wildtype and knockout control animals revealed a diminished expression of PKC δ and ε in Gα11 knockout animals. Conclusion The present study shows that expression of the nPKCs δ and ε in coronary vessels is under control of the g-protein Gα11. The reduced expression of PKC ζ that we observed in coronary arteries from Gα11-knockout mice compared to wildtype controls upon induction of diabetes could reduce apoptosis and promote plaque stability. These findings suggest a mechanism that may in part underlie the therapeutic benefit of RAS inhibition on cardiovascular endpoints in diabetic patients.
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Chen SX, Song T, Zhou SH, Liu YH, Wu SJ, Liu LY. Protective effects of ACE inhibitors on vascular endothelial dysfunction induced by exogenous advanced oxidation protein products in rats. Eur J Pharmacol 2008; 584:368-75. [PMID: 18334254 DOI: 10.1016/j.ejphar.2008.02.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Revised: 01/23/2008] [Accepted: 02/06/2008] [Indexed: 11/28/2022]
Abstract
To explore detrimental effects of advanced oxidation protein products-bovine serum albumin (BSA) on endothelial function and compare the favorable effects of angiotensin-converting enzyme (ACE) inhibitors: captopril and enalapril. Male Sprague-Dawley rats were randomly divided into groups: control, advanced oxidation protein products-BSA, captopril (10, 20 mg/kg/day), enalapril (15 mg/kg/day), and N(G)-nitro-l-arginine methyl ester (l-NAME, 300 mg/kg/day) plus captopril (20 mg/kg/day) groups. All animals were given advanced oxidation protein products-BSA (100 mg/kg/day, i.v.) except for control group (iv. equal volume of PBS). Rats in other groups were received different drugs intragastrically after advanced oxidation protein products-BSA administration. Endothelium-dependent relaxation of thoracic aorta was assayed. Content of nitrite/nitrate (NO), malondialdehyde (MDA), activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and of ACE in Sera, as well as renal function index including blood urea nitrogen and creatinine were measured. After 30 days, the endothelium-dependent relaxation of blood vessels in received advanced oxidation protein products-BSA rats was significantly impaired compared with control rats. The impairment was accompanied by decreases of serum NO, activity of GSH-Px and SOD. Administration of captopril and enalapril not only decreased damage of endothelium-dependent relaxation, but also reverse the changes of MDA levels, NO content and activity of SOD. The protective effect of captopril was abolished by L-NAME. Blood urea nitrogen and creatinine had no significant differences between various groups. ACE activities were decreased in high captopril and enalapril groups, but did not significantly change in other groups. The results suggested that captopril and enalapril have similar effects on endothelial dysfunction induced by advanced oxidation protein products-BSA, which indicated that protective effects of captopril are not related to sulfhydryl group.
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Affiliation(s)
- Shuang-Xiu Chen
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, No. 110 Xiang-Ya Road, Changsha, Hunan 410078, China
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Luo HL, Zang WJ, Lu J, Yu XJ, Lin YX, Cao YX. The Protective Effect of Captopril on Nicotine-Induced Endothelial Dysfunction in Rat. Basic Clin Pharmacol Toxicol 2006; 99:237-45. [PMID: 16930297 DOI: 10.1111/j.1742-7843.2006.pto_494.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study was designed to examine the in vivo and in vitro effects of captopril, an angiotensin-converting enzyme inhibitor, on nicotine-induced endothelial dysfunction in rats. Endothelial dysfunction was induced by exposing isolated rat mesenteric arteries to nicotine (0.01, 0.1, or 1 mM) for 24 hr using an organ culture system, or by treating rats with nicotine (2 mg/kg/day, intraperitoneally) for 4 weeks. The protective effects of captopril were tested by exposing isolated mesenteric arteries to captopril (0.01, 0.03, or 0.1 mM) + nicotine (0.1 mM) for 24 hr, or by treating rats with captopril (3 mg/kg/day, intravenously) + nicotine (2 mg/kg/day, intraperitoneally) for 4 weeks. Exposure of the isolated mesenteric arteries to nicotine induced a significant concentration -dependent inhibition of endothelium-dependent relaxation. Co-culture of segments of mesenteric artery with captopril (0.03 or 0.1 mM) attenuated the nicotine-induced impairment of vasorelaxation in a dose-dependent manner. Administration of nicotine to rats for 4 weeks significantly impaired endothelium-dependent relaxation compared with control rats. This impairment was accompanied by a reduction in nitrite/nitrate, nitric oxide (NO) synthase (NOS), and superoxide dismutase (SOD) activities in the serum and aorta. Chronic captopril treatment not only improved the impairment of endothelium-dependent relaxation, but also prevented the reduction of nitrite/nitrate contents and of NOS and SOD activities in the serum and aorta. However, there were no significant differences in serum angiotensin-converting enzyme activity among the three groups. These results indicate that captopril can be used to attenuate nicotine-induced endothelial dysfunction, an effect that may be related not only to antioxidation, but also to enhancing NO production by preventing the decrease in NOS.
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Affiliation(s)
- Hong-Li Luo
- Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China
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Fu YF, Xiong Y, Guo Z. A reduction of endogenous asymmetric dimethylarginine contributes to the effect of captopril on endothelial dysfunction induced by homocysteine in rats. Eur J Pharmacol 2005; 508:167-75. [PMID: 15680268 DOI: 10.1016/j.ejphar.2004.11.063] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Revised: 11/19/2004] [Accepted: 11/30/2004] [Indexed: 12/22/2022]
Abstract
We examined whether captopril exerts beneficial effect on homocysteine-induced endothelial dysfunction in vivo and whether this effect of captopril is associated with a reduction of endogenous inhibitor of nitric oxide synthase (NOS) asymmetric dimethylarginine (ADMA) in rats. Male Sprague-Dawley rats were given intravenous injections of homocysteine (10 mg/kg/day) to induce endothelial dysfunction. Captopril treatment (3 mg/kg/day, i.v.) was taken in some rats after homocysteine administration. Endothelium-dependent relaxation was tested in aortic rings. Serum levels of ADMA, nitrite/nitrate, malondialdehyde (MDA), and creatinine were measured. Furthermore, superoxide dismutase activity in liver and angiotensin converting enzyme activity in serum were also assayed. Administration of homocysteine to rats for 4 weeks significantly impaired endothelium-dependent relaxation compared with control rats. This impairment of endothelium-dependent relaxation was accompanied by elevated serum concentration of ADMA and decreased serum content of nitrite/nitrate. Moreover, serum concentration of MDA was remarkably increased, whereas liver superoxide dismutase activity was decreased in homocysteine-treated group compared with control. Chronic captopril treatment not only improved the impaired endothelium-dependent relaxation, but also prevented the elevation of serum ADMA and MDA levels, as well as reduction of serum nitrite/nitrate contents and liver superoxide dismutase activity. Serum angiotensin converting enzyme activity and creatinine had no significant difference between the three groups. These results suggest that chronic captopril treatment reduces endogenous inhibitor of NOS in rats with homocysteine injection, which may contribute to the beneficial effect of captopril on homocysteine-induced endothelial dysfunction in vivo, and may be secondary to the antioxidative action of captopril.
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Affiliation(s)
- Yun-Feng Fu
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, 110 Xiang-ya road, Changsha 410078, Hunan, PR China
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Fu YF, Xiong Y, Fu SH. Captopril Restores Endothelium-Dependent Relaxation of Rat Aortic Rings After Exposure to Homocysteine. J Cardiovasc Pharmacol 2003; 42:566-72. [PMID: 14508244 DOI: 10.1097/00005344-200310000-00016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This study was designed to investigate the effects of captopril, an angiotensin-converting enzyme inhibitor, on inhibition of endothelium-dependent relaxation induced by homocysteine in isolated rat aorta. Isometric tension recordings were used to assess inhibitory effects of homocysteine and protective effects of captopril on endothelium-dependent relaxation of aortic rings. Exposure of aortic rings to homocysteine (0.3 approximately 3 mmol/L) for 30 min induced a significant concentration-dependent inhibition of endothelium-dependent relaxation response to acetylcholine (ACh), but did not affect endothelium-independent relaxation response to sodium nitroprusside. Pre-incubation of aortic rings with captopril (3 approximately 30 micromol/L) for 15 min and co-incubation of aortic rings with homocysteine (1 mmol/L) for another 30 min attenuated the inhibition of homocysteine in a dose-dependent manner. Moreover, superoxide dismutase (SOD, 200 U/mL), a scavenger of superoxide anions, reduced homocysteine-induced inhibition. L-Arginine (3 mmol/L), a precursor of nitric oxide (NO), also attenuated the impairment of vasorelaxation induced by homocysteine. However, in the combined presence of SOD and L-arginine, the inhibitory effect of homocysteine was reversed, which was very similar to the effect of 30 micromol/L captopril. These results suggest that captopril can prevent the inhibition of endothelium-dependent relaxation induced by homocysteine in isolated rat aorta, which may be related to scavenging oxygen free radicals and enhancing NO production.
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Affiliation(s)
- Yun-feng Fu
- Department of Pharmacology, Xiang-ya Medical College, Central South University, Hunan, PR China
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Sanz M, Ganado P, Tejerina T. Two angiotensin AT1 receptor antagonists, irbesartan and losartan, effects in cholesterol-fed rabbits. Eur J Pharmacol 2002; 442:99-106. [PMID: 12020687 DOI: 10.1016/s0014-2999(02)01497-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study was performed to examine the long-term effects of irbesartan and losartan, two angiotensin (AT(1)) receptor antagonists, on lipoproteins and vascular responsiveness in vessels isolated from hypercholesterolemic rabbits. Four groups of rabbits (n=40) were used: Group 0 (control group), Group 1 [hypercholesterolemic group, 0.5% (wt./wt.) cholesterol-enriched diet], Group 2 (hypercholesterolemic+irbesartan 10 mg/kg/day) and Group 3 (hypercholesterolemic+losartan 10 mg/kg/day). After 17 weeks of treatment, total cholesterol and low-density lipoproteins levels in irbesartan- and losartan-treated groups were significantly lower than those of Group 1 (alpha=0.05). Furthermore, levels of high-density lipoproteins were higher in the treated groups than in the hypercholesterolemic (alpha=0.05) when we consider the same level of total cholesterol in the hypercholesterolemic and the treated groups. Despite the effect of the drugs on the abovementioned parameters, treatment with irbesartan or losartan did not improve endothelium-dependent and independent relaxation in aortic and mesenteric rings. Treatment with irbesartan and losartan decreased noradrenaline-induced contraction in aortic rings with respect to that in the hypercholesterolemic group (alpha=0.05). In addition, irbesartan treatment improved the increase in serotonin-induced contraction in proximal coronary arteries with respect to that in the hypercholesterolemic group (alpha=0.05). These results indicate that irbesartan and losartan restore noradrenaline-induced contraction in hypercholesterolemic rabbit-isolated arteries and improve lipoprotein profile in cholesterol-fed rabbits.
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Affiliation(s)
- Mercedes Sanz
- Department of Pharmacology, School of Medicine, Complutense University, Madrid, Spain
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Hayek T, Kaplan M, Raz A, Keidar S, Coleman R, Aviram M. Ramipril administration to atherosclerotic mice reduces oxidized low-density lipoprotein uptake by their macrophages and blocks the progression of atherosclerosis. Atherosclerosis 2002; 161:65-74. [PMID: 11882318 DOI: 10.1016/s0021-9150(01)00621-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Foam cell formation, the hallmark of early atherosclerosis, results from cholesterol accumulation in arterial macrophages. Angiotensin-II stimulates foam cell formation and angiotensin converting enzyme (ACE) inhibitors reduce atherosclerosis in animal models. The goal of the present study was to determine the effect of the ACE inhibitor Ramipril on the progression of atherosclerosis in apolipoprotein-E-deficient (E0) mice with already advanced atherosclerosis. Therefore, 4-month-old atherosclerotic E0 mice were treated with Ramipril for 2 and 4 months and compared to age-matched placebo-treated mice, as well as to control young (4-month-old) non-treated E0 mice, for their atherosclerosis. Histomorphometry showed that Ramipril treatment substantially inhibited atherogenesis as shown by 48 and 72% reduction in lesion size at 6 and 8 months of age, respectively, compared to the lesion size in age-matched placebo-treated mice. Moreover, the size of the atherosclerotic lesions in 6- and 8-month-old Ramipril-treated mice was almost identical to the size of atherosclerosis of the 4-month-old control mice. Moreover, Ramipril treatment of E0 mice, significantly reduced oxidized low-density lipoprotein (Ox-LDL) uptake by their peritoneal macrophages (MPM) by 32%, compared to Ox-LDL uptake by MPM from 6-month-old placebo mice, and even reduced it by 12% in comparison to Ox-LDL uptake by MPM from 4-month-old control mice. A significant decrease in the mRNA levels of the Ox-LDL receptor CD36 by 58% was observed in macrophages from 6-month-old Ramipril-treated mice compared to macrophages from the 6-month-old placebo-treated mice. There was even a significant reduction (by 32%) in CD36 mRNA levels in macrophages from the 6-month-old Ramipril-treated mice, compared to the CD36 mRNA levels in macrophages from the 4-month-old control mice. We thus conclude that administration of the ACE inhibitor Ramipril to E0 mice, which already exhibit significant atherosclerosis, blocked the progression of the atherosclerotic lesion build-up, a phenomenon that could be related to Ramipril-induced inhibition of Ox-LDL uptake by macrophages.
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Affiliation(s)
- Tony Hayek
- The Lipid Research Laboratory, The Bruce Rappaport Faculty of Medicine, Technion, The Rappaport Family Institute for Research in the Medical Sciences and Rambam Medical Center, 31096 Haifa, Israel.
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Halkin A, Keren G. Potential indications for angiotensin-converting enzyme inhibitors in atherosclerotic vascular disease. Am J Med 2002; 112:126-34. [PMID: 11835951 DOI: 10.1016/s0002-9343(01)01001-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Angiotensin-converting enzyme (ACE) inhibitors are well established as first-line therapy for patients with left ventricular dysfunction, diabetic patients with hypertension or renal disease, and patients recovering from myocardial infarction. Angiotensin II and bradykinin regulate cellular proliferation, inflammation, and endothelial function, thus playing an important role in the pathogenesis of atherosclerosis. A large body of experimental evidence reporting that ACE inhibitors limit these effects has formed the rationale for major clinical trials of these drugs in the management of atherosclerotic vascular disease. The first trial to be completed demonstrated that ACE inhibition improves the prognosis of patients who have, or are at risk of, atherosclerotic vascular disease, independent of its effects on left ventricular function and hypertension. Expanding the indications for ACE inhibitors is now evidence driven, although the choice of agent for these new indications remains to be determined by further research.
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Affiliation(s)
- Amir Halkin
- Department of Cardiology, Tel Aviv Sourasky Medical Center and the Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Abstract
Studies using both in vitro and in vivo techniques have repeatedly shown that endothelium-dependent vasodilation (EDV) is impaired in different forms of experimental as well as human hypercholesterolemia. Clearly this impaired EDV can be reversed by lowering cholesterol levels by diet or medical therapy. Competitive blocking of L-arginine, changes in nitric oxide synthase activity, increased release of endothelin-1, and inactivation of nitric oxide due to superoxide ions all contribute to the impairment in EDV during dyslipidemia. The oxidation of low density lipoprotein, with its compound lysophosphatidylcholine, plays a critical role in these events. However, data on the role of triglycerides and fat-rich meals regarding EDV are not so consistent as data for cholesterol, although a view that the compositions of individual fatty acids and antioxidants are of major importance is emerging. Thus, this review shows that while impaired EDV is a general feature of hypercholesterolemia, the mechanisms involved and the therapeutic opportunities available still have to be investigated. Furthermore, discrepancies regarding the role of triglycerides and fat content in food may be explained by divergent effects of different fatty acids on the endothelium.
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Affiliation(s)
- Lars Lind
- Department of Medicine, Uppsala University Hospital and AstraZeneca R&D, Möndal, Sweden.
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Strawn WB, Chappell MC, Dean RH, Kivlighn S, Ferrario CM. Inhibition of early atherogenesis by losartan in monkeys with diet-induced hypercholesterolemia. Circulation 2000; 101:1586-93. [PMID: 10747353 DOI: 10.1161/01.cir.101.13.1586] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Angiotensin II may contribute to atherogenesis by facilitating the proliferative and inflammatory response to hypercholesterolemia. This study determined, in a primate model of diet-induced atherosclerosis, the effect of AT(1) blockade on fatty-streak formation, plasma lipids, and surrogate markers of vascular injury. METHODS AND RESULTS Male cynomolgus monkeys fed a diet containing 0.067 mg cholesterol/kJ for 20 weeks were given losartan (180 mg/d, n=6) or vehicle (n=8) for 6 weeks starting at week 12 of the dietary regimen. Arterial pressure, heart rate, plasma total and lipoprotein cholesterol concentrations, and lipoprotein particle sizes and subclass distributions were unaffected by treatment. Losartan caused significant (P<0.05) increases in plasma angiotensin II and angiotensin-(1-7). Compared with vehicle-treated controls, losartan reduced the extent of fatty streak in the aorta, the coronary arteries, and the carotid arteries by approximately 50% (P<0.05). A significant (P<0.05) reduction in the susceptibility of LDL to in vitro oxidation, serum levels of monocyte chemoattractant protein-1, and circulating monocyte CD11b expression were also associated with losartan treatment. In addition, serum levels of vascular cell adhesion molecule-1 and E-selectin did not change during treatment but increased after discontinuation of losartan. Serum C-reactive protein, platelet aggregability, and white cell counts were not modified by losartan. CONCLUSIONS This study demonstrates for the first time an antiatherogenic effect of AT(1) receptor blockade in nonhuman primates. Losartan inhibited fatty-streak formation through mechanisms that may include protection of LDL from oxidation and suppression of vascular monocyte activation and recruitment factors.
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Affiliation(s)
- W B Strawn
- Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Schwemmer M, Sommer O, Koeckerbauer R, Bassenge E. Cardiovascular dysfunction in hypercholesterolemia associated with enhanced formation of AT1-receptor and of eicosanoids. J Cardiovasc Pharmacol Ther 2000; 5:59-68. [PMID: 10687675 DOI: 10.1177/107424840000500108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In hypercholesterolemia with or without atherosclerosis cardiovascular dysfunction and altered signalling of angiotensin (Ang II), nitric oxide (NO), or prostanoids are intimately related to enhanced oxidant stress and concomitant changes in gene expression. We analyzed cardiac angiotensin receptor (AT1) expression and metabolism of Ang II, eicosanoids, and NO in hypercholesterolemic animals. METHODS Guinea pigs were fed a 1% cholesterol diet for 8 weeks (Chol). Hemodynamics were analyzed in Langendorff hearts. Spectrophotometric determination of plasma lipids and radioimmunological detection of eicosanoids/cyclic guanosine monophosphate (cGMP). Activities of NO synthase III (NOS-III) or angiotensin converting enzyme (ACE) were determined by enzymatic assays. AT1 receptor density was assessed by radioligand binding assay. NOS-III mRNAs were quantitated by reverse transcription polymerase chain reaction. RESULTS Hypercholesterolemia was associated with fatty degeneration of the liver and profound myocardial and coronary (e.g., endothelial) dysfunction. In Chol Langendorff hearts we observed significant increases in coronary flow (26.0 +/- 1.0 vs. 17.5 +/- 0.5 mL/min/g tissue) but diminished coronary responses to bradykinin (Bk, 250 ng bolus) or adenosine (Ado, 250 micrograms bolus) (delta CPPBk/Ado: 5 +/- 0.5 vs. 7.2 +/- 1/0.9 +/- 0.1 vs. 1.9 +/- 0.3 cm2 (area under the curve)). AT1 receptor expression was significantly increased in Chol hearts (72 +/- 6.8 vs. 45 +/- 5.6 fmol/mg protein), whereas marked suppression of cardiac activities of ACE (1.96 +/- 0.34 vs. 4.90 +/- 0.20 nmol/min/mg tissue) and of the entire cardiac nitric oxide-cGMP axis (e.g., NOS-III activity: 1.9 +/- 0.4 vs. 3.1 +/- 0.1 pmol/min/mg tissue; NOS-III mRNA: 0.82 +/- 0.16 vs. 1.20 +/- 0.12 arbitrary units; cGMP release: 0.41 +/- 0.02 vs. 0.54 +/- 0.04 pmol/min/g tissue) were shown in Chol. Finally, cardiac release of eicosanoids prostacyclin (PGI2) and thromboxane (TxA2) were significantly enhanced (0.48 +/- 0.05 vs. 0.38 +/- 0.05 and 0.60 +/- 0.10 vs. 0.24 +/- 0.10 ng/min/g tissue, respectively). Enhanced cardiac PGI2 release and suppression of cGMP synthesis in Chol were even more pronounced on stimulation with Bk (38.2 +/- 3.0 vs. 28.2 +/- 2.0 ng/min/g tissue and 1.9 +/- 0.3 vs. 3.0 +/- 0.3 pmol/min/g tissue, respectively). CONCLUSIONS Altered angiotensin-mediated signal transduction probably related to augmented eicosanoid formation does not compensate for the limited endogenous NO production and for cardiovascular dysfunction in hypercholesterolemic guinea pigs. In this context, changes in redox-sensitive regulation of gene expression (AT1 receptor, NOS-III--caused by enhanced oxidant stress--could play a pivotal role.
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Affiliation(s)
- M Schwemmer
- Institute of Applied Physiology, Albert-Ludwigs-University, Freiburg, Germany
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Wilmink HW, Banga JD, Hijmering M, Erkelens WD, Stroes ES, Rabelink TJ. Effect of angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor antagonism on postprandial endothelial function. J Am Coll Cardiol 1999; 34:140-5. [PMID: 10400003 DOI: 10.1016/s0735-1097(99)00154-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The purpose of this study was to determine whether endothelial dysfunction as a consequence of direct postprandial lipid response might be favorably influenced by angiotensin-converting enzyme inhibitors or angiotensin AT1 receptor antagonists. BACKGROUND Postprandial triglyceride-rich lipoproteins cause endothelial dysfunction. Angiotensin-converting enzyme inhibitors have been shown to improve vascular reactivity. For angiotensin II type 1 receptor antagonists this effect is as yet uncertain. METHODS A randomized, double-blind, placebo-controlled crossover study in 30 healthy volunteers, aged 18 to 33 years, evaluated the effect of quinapril (40 mg daily for two weeks) and losartan (50 mg daily for two weeks) on basal as well as postprandial endothelial function measured noninvasively as percentage diameter change in the brachial artery after reactive hyperemia. Endothelium-independent dilation was measured after nitroglycerine spray sublingual. RESULTS An acute oral fat load impaired endothelial function. Flow-mediated vasodilation (FMD) decreased from a median of 6.2% to 4.2% (p < 0.05). There was no significant difference in preprandial endothelial function after two weeks of treatment with either quinapril or losartan compared with placebo in these healthy volunteers. Both quinapril (FMD 6.4% to 6.3%) and losartan (7.1% to 5.4%) prevented endothelial dysfunction induced by an oral fat load, although the protective effect of quinapril appeared to be more profound. The response to the endothelium-independent vasodilator nitroglycerine was unaltered throughout the study. CONCLUSIONS Both losartan and quinapril prevent endothelial dysfunction induced by triglyceride-rich lipoproteins in healthy volunteers. However, the protective effect of quinapril is more pronounced.
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Affiliation(s)
- H W Wilmink
- Division of Internal Medicine, University Hospital Utrecht, The Netherlands
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Yamakoshi J, Kataoka S, Koga T, Ariga T. Proanthocyanidin-rich extract from grape seeds attenuates the development of aortic atherosclerosis in cholesterol-fed rabbits. Atherosclerosis 1999; 142:139-49. [PMID: 9920515 DOI: 10.1016/s0021-9150(98)00230-5] [Citation(s) in RCA: 278] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The aim of this study was to evaluate the antiatherosclerotic effect of proanthocyanidin-rich extracts from grape seeds in cholesterol-fed rabbits. Proanthocyanidin-rich extracts (0.1% and 1% in diets [w/w]) did not appreciably affect the changes in serum lipid profile of cholesterol-fed rabbits. The level of cholesteryl ester hydroperoxides (ChE-OOH) induced by 2,2'-azobis(2-amidinopropane-dihydrochloride (AAPH) were lower in the plasma of rabbits fed proanthocyanidin-rich extract plus cholesterol than in the plasma of rabbits fed cholesterol alone, but not in the low-density lipoprotein (LDL). Aortic malondialdehyde (MDA) content decreased in rabbits fed proanthocyanidin-rich extract. Feeding proanthocyanidin-rich extracts (0.1 and 1% in the diet) to rabbits significantly reduced severe atherosclerosis in the aorta. Immunohistochemical analysis revealed a decrease in the number of oxidized LDL-positive macrophage-derived foam cells in atherosclerotic lesions in the aorta of rabbits fed proanthocyanidin-rich extract. When proanthocyanidin-rich extract was administered orally to rats, proanthocyanidin was detected in the plasma by Porters method but not in the lipoproteins (LDL plus VLDL). In an in vitro experiment using human plasma, proanthocyanidin-rich extract added to the plasma inhibited the oxidation of cholesteryl linoleate in LDL, but not in the LDL isolated after the plasma and the extract were incubated in advance. These results suggested that proanthocyanidins, the major polyphenols in red wine, might trap reactive oxygen species in aqueous series such as plasma and interstitial fluid of the arterial wall, thereby inhibiting oxidation of LDL and showing an antiatherosclerotic activity.
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Affiliation(s)
- J Yamakoshi
- Research and Development Division, Kikkoman Corporation, Noda City, Chiba Pref, Japan
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