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Ross AD, Sheng H, Warner DS, Piantadosi CA, Batinic-Haberle I, Day BJ, Crapo JD. Hemodynamic effects of metalloporphyrin catalytic antioxidants: structure-activity relationships and species specificity. Free Radic Biol Med 2002; 33:1657-69. [PMID: 12488134 DOI: 10.1016/s0891-5849(02)01140-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Superoxide plays a role in blood pressure regulation in certain vascular diseases, however, its involvement in regulating basal blood pressure is uncertain. Vascular superoxide concentrations are limited by extracellular superoxide dismutase (EC-SOD), which is highly expressed in the vasculature of most animal species. Metalloporphyrins are low molecular weight, synthetic, redox-active, catalytic antioxidants that act as SOD mimetics. We evaluated the effects of metalloporphyrins on blood pressure in different animal species. The metalloporphyrin AEOL10113 (5-10 micro /kg iv), but not native or polyethylene glycol-CuZnSOD, caused a dose-dependent reduction in blood pressure in anesthetized rats. AEOL10113 had no effect on blood pressure in mice (wild-type or EC-SOD knockouts), guinea pigs, dogs, or baboons at doses up to 5 mg/kg iv Structure-activity studies indicated that metalloporphyrins with high SOD activity were more effective in lowering rat blood pressure than low-activity analogs. The blood pressure effect of AEOL10113 was not attributable to the release of manganese, nor was it affected by inhibitors of nitric oxide synthase (L-NAME) and guanylate cyclase (ODQ, 8-bromo-cGMP, and methylene blue) or nitric oxide scavengers (HbAo). Chlorpheniramine attenuated the effect, suggesting that the blood pressure response in rats is related to histamine release rather than the protection of nitric oxide.
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Affiliation(s)
- Aron D Ross
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80209, USA.
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Cai H, Li Z, Dikalov S, Holland SM, Hwang J, Jo H, Dudley SC, Harrison DG. NAD(P)H oxidase-derived hydrogen peroxide mediates endothelial nitric oxide production in response to angiotensin II. J Biol Chem 2002; 277:48311-7. [PMID: 12377764 DOI: 10.1074/jbc.m208884200] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently, it has been shown that the exogenous addition of hydrogen peroxide (H(2)O(2)) increases endothelial nitric oxide (NO(.)) production. The current study is designed to determine whether endogenous levels of H(2)O(2) are ever sufficient to stimulate NO(.) production in intact endothelial cells. NO(.) production was detected by a NO(.)-specific microelectrode or by an electron spin resonance spectroscopy using Fe(2+)-(DETC)(2) as a NO(.)-specific spin trap. The addition of H(2)O(2) to bovine aortic endothelial cells caused a potent and dose-dependent increase in NO(.) release. Incubation with angiotensin II (10(-7) mol) elevated intracellular H(2)O(2) levels, which were attenuated with PEG-catalase. Angiotensin II increased NO(.) production by 2-fold, and this was prevented by Losartan and by PEG-catalase, suggesting a critical role of AT1 receptor and H(2)O(2) in this response(.) In contrast, NO(.) production evoked by either bradykinin or calcium ionophore was unaffected by PEG-catalase. As in bovine aortic endothelial cells, angiotensin II doubled NO(.) production in aortic endothelial cells from C57BL/6 mice but had no effect on NO(.) production in endothelial cells from p47(phox-/-) mice. In contrast, stimulated NO(.) production to a similar extent in endothelial cells from wild-type and p47(phox-/-) mice. In summary, the present study provides direct evidence that endogenous H(2)O(2), derived from the NAD(P)H oxidase, mediates endothelial NO(.) production in response to angiotensin II. Under disease conditions associated with elevated levels of angiotensin II, this response may represent a compensatory mechanism. Because angiotensin II also stimulates O(2)() production from the NAD(P)H oxidase, the H(2)O(2) stimulation of NO(.) may facilitate peroxynitrite formation in response to this octapeptide.
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Affiliation(s)
- Hua Cai
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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353
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Hanna IR, Taniyama Y, Szöcs K, Rocic P, Griendling KK. NAD(P)H oxidase-derived reactive oxygen species as mediators of angiotensin II signaling. Antioxid Redox Signal 2002; 4:899-914. [PMID: 12573139 DOI: 10.1089/152308602762197443] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Angiotensin II has been shown to participate in both physiological processes, such as sodium and water homeostasis and vascular contraction, and pathophysiological processes, including atherosclerosis and hypertension. The effects of this molecule on vascular tissue are mediated at least in part by the modification of the redox milieu of its target cells. Angiotensin II has been shown to activate the vascular NAD(P)H oxidase(s) resulting in the production of reactive oxygen species, namely superoxide and hydrogen peroxide. In this article, we review what is known about the molecular steps that link angiotensin II and its receptor to production of reactive oxygen species and subsequent redox-mediated events, focusing on the structural and functional properties of the vascular NAD(P)H oxidases and their downstream mediators. As such, we provide a framework linking angiotensin II to crucial vascular pathologies, such as hypertension, atherosclerosis, and restenosis after angioplasty, by means of the NAD(P)H-dependent oxidases and their effector molecules.
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Affiliation(s)
- Ibrahim R Hanna
- Emory University, Division of Cardiology, Atlanta, GA 30322, USA
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354
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355
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Abstract
The endothelium, by releasing nitric oxide (NO), promotes vasodilation and inhibits inflammation, thrombosis, and vascular smooth muscle cell proliferation. These biological actions of NO make it an important component in the endogenous defense against atherosclerosis and its overt clinical complications. Loss of the functional integrity of the endothelium, as seen commonly in the milieu of cardiovascular risk factors, plays an integral role in all stages of atherosclerosis from lesion initiation to plaque rupture. A number of established techniques can assess endothelial function in human vascular beds. The outcome of endothelial testing has profound prognostic implications and is an independent predictor of atherosclerosis disease progression and cardiovascular event rates. The large clinical benefit of statins and angiotensin-converting enzyme inhibitors in patients with atherosclerosis involves favorable effects of endothelial function. Studies of endothelial function represent a prime example of a successful application of insights derived from vascular biology at the bedside.
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Affiliation(s)
- Dominik Behrendt
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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356
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Kyaw M, Yoshizumi M, Tsuchiya K, Kirima K, Suzaki Y, Abe S, Hasegawa T, Tamaki T. Antioxidants inhibit endothelin-1 (1-31)-induced proliferation of vascular smooth muscle cells via the inhibition of mitogen-activated protein (MAP) kinase and activator protein-1 (AP-1). Biochem Pharmacol 2002; 64:1521-31. [PMID: 12417265 DOI: 10.1016/s0006-2952(02)01349-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously found that human chymase cleaves big endothelins (ETs) at the Tyr(31)-Gly(32) bond and produces 31-amino acid ETs (1-31), without any further degradation products. In the present study, we investigated the effects of various antioxidants on the ET-1 (1-31)-induced change in intracellular signaling and proliferation of cultured rat aortic smooth muscle cells (RASMC). ET-1 (1-31) stimulated rapid and significant activation of the mitogen-activated protein (MAP) kinase family, i.e. extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH(2)-terminal kinase (JNK), and p38 MAPK, in RASMC to an extent similar to that of ET-1. All of the antioxidants examined, i.e. N-acetyl-L-cysteine (NAC), diphenyleneiodonium chloride (DPI), and L-(+)-ascorbic acid (ascorbic acid), inhibited both ET-1 (1-31)- and ET-1-induced JNK and p38 MAPK activation but not ERK1/2 activation. Electron paramagnetic resonance (EPR) spectroscopy measurements revealed that NAC, DPI, and ascorbic acid inhibited xanthine oxidase-induced superoxide (O(2)(.-)) generation in a cell-free system. ET-1 (1-31) in addition to ET-1 increased the generation of cellular reactive oxygen species (ROS) in RASMC. ET-1 (1-31)- and ET-1-induced cellular ROS generation was inhibited similarly by NAC, DPI, and ascorbic acid in RASMC. Gel-mobility shift analysis showed that ET-1 (1-31) and ET-1 caused an increase in activator protein-1 (AP-1)-DNA binding activity in RASMC that was inhibited by the above three antioxidants. ET-1 (1-31) increased [3H]thymidine incorporation into cells to an extent similar to that of ET-1. This ET-1 (1-31)-induced increase in [3H]thymidine incorporation was also inhibited by NAC and DPI, but not by ascorbic acid. These results suggest that antioxidants inhibit ET-1 (1-31)-induced RASMC proliferation by inhibiting ROS generation within the cells. The underlying mechanisms of the inhibition of cellular proliferation by antioxidants may be explained, in part, by the inhibition of JNK activation and the resultant inhibition of AP-1-DNA binding.
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Affiliation(s)
- Moe Kyaw
- Department of Pharmacology, The University of Tokushima School of Medicine, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
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357
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Abstract
Interstitial fibrosis has a major role in the progression of renal diseases. Several animal models are available for the study of renal fibrosis. The models of aminonucleoside-induced nephrotic syndrome, cyclosporin nephrotoxicity, and passive Heyman nephritis are characterized by molecular and cellular events similar to those that occur in obstructive nephropathy. Additionally, inhibition of angiotensin-converting enzyme exerts salutary effects on the progression of renal fibrosis in obstructive nephropathy. Unilateral ureteral obstruction (UUO) has emerged as an important model for the study of the mechanisms of renal fibrosis and also for the evaluation of the impact of potential therapeutic approaches to ameliorate renal disease. Many quantifiable pathophysiological events occur over the span of 1 wk of UUO, making this an attractive model for study. This paper reviews some of the ongoing studies that utilized a rodent model of UUO. Some of the findings of the animal model have been compared with observations made in patients with obstructive nephropathy. Most of the evidence suggests that the rodent model of UUO is reflective of human renal disease processes.
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Affiliation(s)
- Saulo Klahr
- Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, Missouri 63110-1092, USA.
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358
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Warnholtz A, Mollnau H, Heitzer T, Kontush A, Möller-Bertram T, Lavall D, Giaid A, Beisiegel U, Marklund SL, Walter U, Meinertz T, Munzel T. Adverse effects of nitroglycerin treatment on endothelial function, vascular nitrotyrosine levels and cGMP-dependent protein kinase activity in hyperlipidemic Watanabe rabbits. J Am Coll Cardiol 2002; 40:1356-63. [PMID: 12383586 DOI: 10.1016/s0735-1097(02)02133-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE With the present studies we sought to determine how treatment with nitroglycerin (NTG) affects endothelial function, oxidative stress and nitric oxide (NO)-downstream signaling in Watanabe heritable hyperlipidemic rabbits (WHHL). BACKGROUND In vitro experiments have demonstrated potent antiatherosclerotic effects of NO suggesting that treatment with NO-donors such as NTG could compensate for the diminished availability of endothelial NO. Nitric oxide may, however, not only be scavenged by reaction with endothelium-derived superoxide but also form the potent oxidant and inhibitor of vascular function, peroxynitrite (ONOO(-)). METHODS Watanabe heritable hyperlipidemic rabbits were treated for three days with NTG patches. Normolipidemic New Zealand White rabbits (NZWR) served as controls. Endothelial function was assessed ex vivo with organ chamber experiments and vascular superoxide was quantified using lucigenin (5 and 250 microM) and CLA-enhanced chemiluminescence. Vascular ONOO(-) formation was determined using nitrotyrosine antibodies. The activity of the cGMP-dependent kinase (cGK-I) was assessed by determining the phosphorylation of vasodilator-stimulated phosphoprotein VASP (P-VASP). RESULTS Nitroglycerin treatment caused endothelial dysfunction in NZWR and WHHL, associated with an increase in superoxide and ONOO(-) production and a substantial drop in cGK-I activity. In vivo NTG-treatment decreased lipophilic antioxidants (alpha- and beta-carotene) in NZWR and WHHL. Treatment of NZWR with NTG also decreased plasma extracellular superoxide dismutase (EC-SOD)-activity. CONCLUSIONS Nitroglycerin treatment of WHHL with exogenous NO worsens rather than improves endothelial dysfunction secondary to increased formation of superoxide and/or peroxynitrite leading to decreased cGK-I activity. The decrease in plasma levels of alpha- and beta-carotene may be at least in part due to a decrease in EC-SOD activity.
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Affiliation(s)
- Ascan Warnholtz
- Division of Cardiology, University Hospital Eppendorf, Hamburg, Germany
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359
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Landmesser U, Cai H, Dikalov S, McCann L, Hwang J, Jo H, Holland SM, Harrison DG. Role of p47(phox) in vascular oxidative stress and hypertension caused by angiotensin II. Hypertension 2002; 40:511-5. [PMID: 12364355 PMCID: PMC4734745 DOI: 10.1161/01.hyp.0000032100.23772.98] [Citation(s) in RCA: 427] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypertension caused by angiotensin II is dependent on vascular superoxide (O2*-) production. The nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase is a major source of vascular O2*- and is activated by angiotensin II in vitro. However, its role in angiotensin II-induced hypertension in vivo is less clear. In the present studies, we used mice deficient in p47(phox), a cytosolic subunit of the NADPH oxidase, to study the role of this enzyme system in vivo. In vivo, angiotensin II infusion (0.7 mg/kg per day for 7 days) increased systolic blood pressure from 105+/-2 to 151+/-6 mm Hg and increased vascular O2*- formation 2- to 3-fold in wild-type (WT) mice. In contrast, in p47(phox-/-) mice the hypertensive response to angiotensin II infusion (122+/-4 mm Hg; P<0.05) was markedly blunted, and there was no increase of vascular O2*- production. In situ staining for O2*- using dihydroethidium revealed a marked increase of O2*-production in both endothelial and vascular smooth muscle cells of angiotensin II-treated WT mice, but not in those of p47(phox-/-) mice. To directly examine the role of the NAD(P)H oxidase in endothelial production of O2*-, endothelial cells from WT and p47(phox-/-) mice were cultured. Western blotting confirmed the absence of p47(phox) in p47(phox-/-) mice. Angiotensin II increased O2*- production in endothelial cells from WT mice, but not in those from p47(phox-/-) mice, as determined by electron spin resonance spectroscopy. These results suggest a pivotal role of the NAD(P)H oxidase and its subunit p47(phox) in the vascular oxidant stress and the blood pressure response to angiotensin II in vivo.
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Affiliation(s)
- Ulf Landmesser
- Division of Cardiology, Emory University School of Medicine and Atlanta Veterans Administration Hospital, Atlanta, Ga 30322, USA
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360
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Abstract
Nitric oxide degradation linked to endothelial dysfunction plays a central role in cardiovascular diseases. Superoxide producing enzymes such as NADPH oxidase and xanthine oxidase are responsible for NO degradation as they generate a variety of reactive oxygen species (ROS). Moreover, superoxide is rapidly degraded by superoxide dismutase to produce hydrogen peroxide leading to the uncoupling of NO synthase and production of increased amount of superoxide. Angiotensin II is an important stimulus of NADPH oxidase. Through its AT(1) receptor, Ang II stimulates the long-term increase of several membrane component of NADPH oxidase such as P(22) phox or nox-1 and causes an increased activity of NADPH oxidase with inactivation of NO leading to impaired endothelium-dependent vasorelaxation, vascular smooth muscle cell hypertrophy, proliferation and migration, extracellular matrix formation, thrombosis, cellular infiltration and inflammatory reaction. Several preclinical and clinical studies have now confirmed the involvement of the AT(1) receptor in endothelial dysfunction. It is proposed that the AT(2) receptor counterbalances the deleterious effect of the Ang II-induced AT(1) receptor stimulation through bradykinin and NOS stimulation. This mechanism could be especially relevant in pathological cases when the NADPH oxidase activity is blocked with an AT(1) receptor antagonist.
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361
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Nishimoto M, Takai S, Fukumoto H, Tsunemi K, Yuda A, Sawada Y, Yamada M, Jin D, Sakaguchi M, Nishimoto Y, Sasaki S, Miyazaki M. Increased local angiotensin II formation in aneurysmal aorta. Life Sci 2002; 71:2195-205. [PMID: 12204777 DOI: 10.1016/s0024-3205(02)01998-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We investigated the levels and locations of angiotensin II-forming enzymes, angiotensin converting enzyme (ACE) and chymase, in aneurysmal and normal aortas. Aneurysmal aortic specimens (n = 14) were obtained at the time of operative aneurysm repair from 14 patients ranging in age from 57 to 84 y. Normal aortic specimens (n = 16) were obtained from 16 patients (48 to 72 y) who underwent coronary artery bypass surgery. The ACE and chymase activities were determined using each specimen. Sections of each specimen were immunostained with antibodies for ACE and chymase. The ACE activities in the aneurysmal and normal aortas were 0.82 +/- 0.10 and 0.14 +/- 0.05 mU/mg protein, respectively, and this difference was significant. The chymase activities in the aneurysmal and normal aortas were 17.9 +/- 2.40 and 1.02 +/- 0.18 mU/mg protein, respectively, and this difference was also significant. In the aneurysmal aorta, ACE-positive cells were detected with macrophages in the intima and media and chymase-positive cells were detected with mast cells in the media and adventitia, whereas positive ACE and chymase cells in the normal aorta were located only in the endothelium and adventitia, respectively. Angiotensin II-forming enzymes, chymase and ACE, were significantly increased in the aneurysmal aorta, and increased angiotensin II may be associated with the development of aneurysmal formations.
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Affiliation(s)
- Masayoshi Nishimoto
- Department of Pharmacology, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki City, Osaka 569-8686, Japan
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362
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Abstract
The renin-angiotensin system plays a major role in the pathogenesis of atherosclerosis. Most known effects of angiotensin II are mediated via activation of the AT(1)-receptor, which is in turn influenced to a great degree by levels of expression of the AT(1)-receptor. AT(1)-receptor activation is not only involved in vasoconstriction, water and salt homoeostasis and control of other neurohumoral systems, but also induces reactive oxygen species production, cellular hypertrophy and hyperplasia and apoptosis. Expression of this G-protein-coupled receptor is regulated by multiple factors. Among other conditions, oestrogen deficiency and hypercholesterolaemia increase AT(1)-receptor expression. Experimental data suggest that this augments the actions of angiotensin II, contributes to endothelial dysfunction, increases vascular production of reactive oxygen species, and via these mechanisms promotes atherosclerosis. Because of this, AT(1)-receptor regulation is likely to be critical in the development and progression of vascular lesions. Interventional studies demonstrated that ACE inhibitors which reduce AT(1)-receptor activation, improve endothelial dysfunction and inhibit onset and progression of atherosclerosis. The more specific AT(1)-receptor antagonists have also been shown to decrease blood pressure, protect renal function and to improve endothelial function. Thus, there is compelling evidence that AT(1)-receptor activation participates in the pathogenesis of atherosclerosis, and more importantly, that treatment regimens aiming at inhibition of AT(1)-receptor activation are promising anti-atherosclerotic therapeutic options.
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Affiliation(s)
- G Nickenig
- Medizinische Klinik und Poliklinik Innere Medizin III, Universität des Saarlandes, Homburg/Saar, Germany.
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363
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Jones RWA, Rees RW, Minhas S, Ralph D, Persad RA, Jeremy JY. Oxygen free radicals and the penis. Expert Opin Pharmacother 2002; 3:889-97. [PMID: 12083989 DOI: 10.1517/14656566.3.7.889] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Penile erection is dependent upon vascular smooth muscle relaxation in erectile tissue and penile arteries, the principal mediator of relaxation being nitric oxide (NO). Evidence from basic scientific studies indicates that oxidative stress mediated through the superoxide radical (superoxide) and other reactive oxygen species (ROS) may be central to impaired cavernosal function in erectile dysfunction (ED). Increased inactivation of NO by superoxide results in impaired penile NO transmission and smooth muscle relaxation. Furthermore, propagation of endothelial dysfunction by ROS may result in chronic impairment of penile vascular function, a process analogous to early atherogenesis. Indeed, ED and atherosclerosis are closely linked through shared risk factors. Given our current understanding of ED pathophysiology, antioxidants may be of benefit in both the short- and long-term. Evidence supporting the paradigm of antioxidant therapy for the prevention or treatment of ED is presented herein.
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Affiliation(s)
- R W A Jones
- Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK
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364
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Niebauer J, Tsao PS, Lin PS, Pratt RE, Cooke JP. Cholesterol-induced upregulation of angiotensin II and its effects on monocyte-endothelial interaction and superoxide production. Vasc Med 2002; 6:133-8. [PMID: 11789966 DOI: 10.1177/1358836x0100600302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Atherogenesis involves an early endothelial dysfunction hallmarked by elevated free radical production and increased adhesiveness for monocytes. It was hypothesized that activation of the tissue renin angiotensin system may contribute to the endothelial alteration. To test this hypothesis, thoracic aortae were isolated from normocholesterolemic (NC; n = 6) and hypercholesterolemic (HC; n = 6; diet: 0.5% cholesterol; 6 weeks) New Zealand white rabbits, and incubated for 2 h with the angiotensin II (Ang II) receptor antagonist Sar-1,Ile-8-Ang II, the antioxidant pyrolidine dithiocarbamate (PDTC) and the protein kinase C (PKC) antagonist staurosporin. Superoxide production from aortic segments was measured by lucigenin-enhanced chemiluminescence. In comparison to the normocholesterolemic state, hypercholesterolemia led to a significant increase in superoxide production (221 +/- 44%, p < 0.02); this was reduced by ex vivo treatment of the vessel segment with Ang II-antagonist (to 130 +/- 29%; p < 0.04 vs HC), or PKC-antagonist (to 86 +/- 26%; p < 0.001 vs HC), or PDTC (to 103 +/- 27%; p < 0.02 vs HC). Monocyte-endothelial interaction was assessed by functional binding assay. When compared to normocholesterolemic rabbits, hypercholesterolemia led to a twofold increase in monocyte binding (74 +/- 13 vs 37 +/- 4 monocytoid cells per high power field (m/hpf); p < 0.03). The Ang II-antagonist and the PKC-antagonist led to a normalization of monocyte-endothelial binding (Ang II-antagonist: 37 +/- 9 m/hpf; PKC-antagonist: 41 +/- 17 m/hpf; p < 0.05). In conclusion, these results indicate that hypercholesterolemia activates the tissue renin angiotensin system, which results in an increased endothelial production of superoxide and monocyte adhesiveness. Ang II-antagonist inhibits free radical production and monocyte adhesion through a mechanism which may include PKC.
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Affiliation(s)
- J Niebauer
- Division of Cardiovascular Medicine, Stanford University, CA 94305-5246, USA
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365
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Williams IL, Wheatcroft SB, Shah AM, Kearney MT. Obesity, atherosclerosis and the vascular endothelium: mechanisms of reduced nitric oxide bioavailability in obese humans. Int J Obes (Lond) 2002; 26:754-64. [PMID: 12037644 DOI: 10.1038/sj.ijo.0801995] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2001] [Revised: 11/16/2001] [Accepted: 12/20/2001] [Indexed: 11/08/2022]
Abstract
It is now well established that obesity is an independent risk factor for the development of coronary artery atherosclerosis. The maintenance of vascular homeostasis is critically dependent on the continued integrity of vascular endothelial cell function. A key early event in the development of atherosclerosis is thought to be endothelial cell dysfunction. A primary feature of endothelial cell dysfunction is the reduced bioavailability of the signalling molecule nitric oxide (NO), which has important anti atherogenic properties. Recent studies have produced persuasive evidence showing the presence of endothelial dysfunction in obese humans NO bioavailability is dependent on the balance between its production by a family of enzymes, the nitric oxide synthases, and its reaction with reactive oxygen species. The endothelial isoform (eNOS) is responsible for a significant amount of the NO produced in the vascular wall. NO production can be modulated in both physiological and pathophysiological settings, by regulation of the activity of eNOS at a transcriptional and post-transcriptional level, by substrate and co-factor provision and through calcium dependent and independent signalling pathways. The present review discusses general mechanisms of reduced NO bioavailability including factors determining production of both NO and reactive oxygen species. We then focus on the potential factors responsible for endothelial dysfunction in obesity and possible therapeutic interventions targetted at these abnormalities.
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Affiliation(s)
- I L Williams
- Department of Cardiology, Guy's, King's and St Thomas' School of Medicine, King's College London, London, UK.
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366
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Herrmann J, Best PJ, Ritman EL, Holmes DR, Lerman LO, Lerman A. Chronic endothelin receptor antagonism prevents coronary vasa vasorum neovascularization in experimental hypercholesterolemia. J Am Coll Cardiol 2002; 39:1555-61. [PMID: 11985922 DOI: 10.1016/s0735-1097(02)01798-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The purpose of this study was to test the hypothesis that endothelin (ET) receptor antagonism reduces coronary vasa vasorum neovascularization in experimental hypercholesterolemia. BACKGROUND Experimental hypercholesterolemia is associated with increased expression of ET-1, an endothelium-derived peptide with vasoconstricting, mitogenic and angiogenic properties, in the coronary arterial wall as well as with vasa vasorum neovascularization. A pathomechanistic role of the endogenous ET system in vasa vasorum neovascularization in hypercholesterolemia has, however, remained uncertain so far. METHODS Female domestic pigs were placed on a normal diet (N; n = 7) or on a hypercholesterolemic diet without (HC; n = 6) or with ET-A receptor antagonism (ABT-627, 4 mg/kg/day; HC + ET-A; n = 6). After 12 weeks, coronary vasa vasorum structure was assessed by three-dimensional microscopic computed tomography, expression of vascular endothelial growth factor (VEGF) within the coronary arterial wall by Western blotting and immunostaining. RESULTS Compared with the N group, plasma concentrations of low-density lipoprotein cholesterol were higher in both the HC and HC + ET-A groups (36 +/- 3 mg/dl vs. 312 +/- 153 mg/dl and 303 +/- 113 mg/dl, p < 0.01). Vasa vasorum density was higher in the HC group compared with the N group (4.7 +/- 1.8 per mm(2) vs. 2.5 +/- 1.5 per mm(2); p < 0.05) and was preserved in the HC + ET-A group (3.2 +/- 0.7 per mm(2)). In parallel, increase in VEGF expression in the coronary arterial wall in the HC group was preserved in the HC + ET-A group. CONCLUSIONS The current study demonstrates that chronic endothelin receptor antagonism prevents the increase in VEGF expression and vasa vasorum density of coronary arteries in experimental hypercholesterolemia. These findings support a role for the endogenous ET system in vasa vasorum neovascularization in early coronary atherosclerosis.
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Affiliation(s)
- Joerg Herrmann
- Division of Cardiovascular Diseases, Mayo Clinic Rochester, Rochester, Minnesota 55905, USA
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367
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Abstract
The possible inhibition of lipid deposition into vascular tissues by a novel angiotensin II type 1 receptor antagonist, olmesartan, was investigated in a primate high-cholesterol model. Twelve monkeys that were fed a high-cholesterol (4% cholesterol and 6% corn oil) diet for 6 months were divided into two groups: one group was given olmesartan medoxomil (10 mg/kg per day), and the other group was given no medication. A further control group of six monkeys was fed a normal diet throughout the study. The level of low-density lipoprotein (LDL) cholesterol was increased by the high-cholesterol diet, whereas that of high-density lipoprotein (HDL) cholesterol was decreased. Olmesartan decreased the areas of lipid deposition on the aortic surface and intimal cross-section area, but not the mean blood pressure and the levels of LDL and HDL cholesterol. The relaxation response of isolated carotid arteries to acetylcholine was suppressed in the high-cholesterol group, but this was improved by olmesartan. Olmesartan inhibited the accumulation of macrophages in the intimal layer. Serum levels of transforming growth factor (TGF)-beta1, macrophage colony-stimulating factor (M-CSF) and intracellular adhesion molecule (ICAM)-1 were increased in monkeys fed the high-cholesterol diet, but they were suppressed by olmesartan, although the decrease was not significant. Olmesartan reduced lipid deposition, accompanied by the improvement of vascular functions and the inhibition of macrophage accumulation in the intimal layer and showed a trend towards the suppression of serum TGF-beta1, M-CSF and ICAM-1.
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Affiliation(s)
- M Miyazaki
- Department of Pharmacology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki City, Osaka 569-8686, Japan.
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368
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Brar SS, Kennedy TP, Sturrock AB, Huecksteadt TP, Quinn MT, Murphy TM, Chitano P, Hoidal JR. NADPH oxidase promotes NF-kappaB activation and proliferation in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2002; 282:L782-95. [PMID: 11880305 DOI: 10.1152/ajplung.00206.2001] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evidence is rapidly accumulating that low-activity-reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases homologous to that in phagocytic cells generate reactive oxygen species as signaling intermediates in both endothelium and vascular smooth muscle. We therefore explored the possibility of such an oxidase regulating growth of airway smooth muscle (AWSM). Proliferation of human AWSM cells in culture was inhibited by the antioxidants catalase and N-acetylcysteine, and by the flavoprotein inhibitor diphenylene iodonium (DPI). Membranes prepared from human AWSM cells generated superoxide anion (O) measured by superoxide dismutase-inhibitable lucigenin chemiluminescence, with a distinct preference for NADPH instead of reduced nicotinamide adenine dinucleotide as substrate. Chemiluminescence was also inhibited by DPI, suggesting the presence of a flavoprotein containing oxidase generating O as a signaling molecule for cell growth. Examination of human AWSM cells by reverse transcriptase-polymerase chain reaction consistently demonstrated transcripts with sequences identical to those reported for p22(phox). Transfection with p22(phox) antisense oligonucleotides reduced human AWSM proliferation. Inhibition of NADPH oxidase activity with DPI prevented serum-induced activation of nuclear factor-kappaB (NF-kappaB), and overexpression of a superrepressor form of the NF-kappaB inhibitor IkappaBalpha significantly reduced human AWSM growth. These findings suggest that an NADPH oxidase containing p22(phox) regulates growth-factor responsive human AWSM proliferation, and that the oxidase signals in part through activation of the prototypical redox-regulated transcription factor NF-kappaB.
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Affiliation(s)
- Sukhdev S Brar
- Department of Internal Medicine, Cannon Research Center, Carolinas Medical Center, Charlotte, NC 28232, USA
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369
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Shihabi A, Li WG, Miller FJ, Weintraub NL. Antioxidant therapy for atherosclerotic vascular disease: the promise and the pitfalls. Am J Physiol Heart Circ Physiol 2002; 282:H797-802. [PMID: 11834471 DOI: 10.1152/ajpheart.2002.282.3.h797] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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370
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Katz SD, Zheng H. Peripheral limitations of maximal aerobic capacity in patients with chronic heart failure. J Nucl Cardiol 2002; 9:215-25. [PMID: 11986567 DOI: 10.1067/mnc.2002.123183] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Stuart D Katz
- Yale University School of Medicine, Section of Cardiovascular Medicine, Heart Failure Center, New Haven, Conn 06510, USA.
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371
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Rubbo H, Trostchansky A, Botti H, Batthyány C. Interactions of nitric oxide and peroxynitrite with low-density lipoprotein. Biol Chem 2002; 383:547-52. [PMID: 12033442 DOI: 10.1515/bc.2002.055] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Nitric oxide (*NO) is a free radical species that diffuses and concentrates in the hydrophobic core of low-density lipoprotein (LDL) to serve as a potent inhibitor of lipid oxidation processes. Peroxynitrite (PN), the product of the diffusion-limited reaction between *NO and superoxide (O2*-) represents a relevant mediator of oxidative modifications in LDL. The focus of this review is the analysis of interactions between *NO and PN and its secondary reactions with oxygen radicals on LDL oxidation, which are relevant in the development of the early steps as well as progression of atherosclerosis. We propose that the balance between rates of PN and *NO production, which greatly depends on oxidative stress processes within the vascular wall, will critically determine the final extent of oxidative LDL modifications leading or not to scavenger receptor-mediated LDL uptake and foam cell formation.
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Affiliation(s)
- Homero Rubbo
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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372
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Zhu BQ, Sievers RE, Browne AEM, Hillman RT, Chair K, Lee RJ, Chatterjee K, Glantz SA, Parmley WW. The renin-angiotensin system does not contribute to the endothelial dysfunction and increased infarct size in rats exposed to second hand smoke. J Renin Angiotensin Aldosterone Syst 2002; 3:54-60. [PMID: 11984749 DOI: 10.3317/jraas.2002.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
INTRODUCTION Both second hand smoke (SHS) and the renin-angiotensin system (RAS) contribute to endothelial dysfunction and increased infarct size in a rat ischaemia-reperfusion model. However, the potential interaction between SHS and the RAS is unknown. METHODS Eighty-four rats were randomised into four groups: group C was a normal control; L was given 40 mg/kg/day of losartan in drinking water; SC and SL were exposed to SHS (smoking chamber) and given regular water or 40 mg/kg/day of losartan in drinking water, respectively. After six weeks of pre-treatment, rats were subjected to 17 minutes of left coronary artery occlusion and 2 hours of reperfusion with haemodynamic and ECG monitoring. RESULTS Haemodynamics were not significantly different among the four groups. Losartan increased the threshold for ventricular fibrillation (p=0.0001) and reduced spontaneous ventricular arrhythmias (p=0.002) during ischaemia-reperfusion, while SHS did not (p=0.713, 0.110), and there was no interaction between losartan and SHS. The maximal endothelium-dependent vasorelaxation induced by a calcium ionophore (A23187) was increased by losartan (p=0.007). Myocardial infarct size was smaller in the losartan groups (p=0.032), larger in the SHS groups (p=0.0001), and there was no significant interaction. CONCLUSION In conclusion, losartan decreased infarct size and increased endothelium-dependent vasorelaxation. SHS exposure impaired endothelial function and increased infarct size. The effects of losartan and SHS were consistently independent of each other. These results suggest that the RAS does not contribute to the adverse effects of SHS.
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Affiliation(s)
- Bo-qing Zhu
- Department of Medicine, University of California, San Francisco 94143-0124, USA
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373
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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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374
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Keidar S, Heinrich R, Kaplan M, Aviram M. Oxidative stress increases the expression of the angiotensin-II receptor type 1 in mouse peritoneal macrophages. J Renin Angiotensin Aldosterone Syst 2002; 3:24-30. [PMID: 11984744 DOI: 10.3317/jraas.2002.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Angiotensin II (Ang II) has been shown to accelerate atherogenesis, and the cellular Ang II type 1 (AT(1))-receptor mediates most of Ang II-induced pro-atherogenic effects. In this study we have examined the effect of macrophage oxidative stress on cellular AT(1)-receptor expression. Mouse peritoneal macrophages (MPM) from apolipoprotein-E deficient (E(0)) mice at increasing ages (1 6 months) demonstrated an age-dependent increase in cellular lipid-peroxides (PD) content. In parallel, the AT(1)-receptor mRNA and protein levels both increased by up to 3.7-fold and 1.7-fold, respectively, in MPM from 6-month old mice compared with 1-month old mice. Vitamin E supplementation to E(0) mice significantly decreased the MPM PD content and macrophage AT(1)-receptor mRNA expression compared with placebo-treated mice. The role of oxidative stress in the cellular expression of AT(1)-receptors was further demonstrated by manipulation of macrophage glutathione content. Buthionine-sulfoximine, a glutathione synthesis inhibitor, increased MPM PD content and AT(1)-receptor mRNA expression, whereas L-2-oxothiazolidine-4-carboxylic acid, that contributes to glutathione synthesis, reduced macrophage PD and AT(1)-receptor mRNA expression. Incubation of MPM with oxidised low-density lipoproteins (LDL) led to a significant, dose-dependent and time-dependent increase in macrophage AT(1)-receptor mRNA and protein expression, compared with control cells. In contrast, native LDL or acetylated LDL did not significantly affect macrophage AT(1)-receptor mRNA expression. In conclusion, our findings suggest that oxidative stress in macrophages induces AT(1)-receptor expression. This phenomenon can stimulate the interaction of Ang II with macrophages and hence accelerate macrophage foam cell formation and early atherogenesis.
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Affiliation(s)
- Shlomo Keidar
- The Lipid Research Laboratory, Technion Faculty of Medicine, The Rappaport Family Institute in the Medical Sciences and Rambam Medical Center, Haifa, Israel.
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375
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Takeshita S, Inoue N, Gao D, Rikitake Y, Kawashima S, Tawa R, Sakurai H, Yokoyama M. Lysophosphatidylcholine enhances superoxide anions production via endothelial NADH/NADPH oxidase. J Atheroscler Thromb 2002; 7:238-46. [PMID: 11521688 DOI: 10.5551/jat1994.7.238] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Reactive oxygen species (ROS) including superoxide anions (O2(-)) play a key role in atherogenesis, and endothelial cells have the ability to generate ROS. To investigate the enzymatic sources of ROS and the effects of lysophosphatidylcholine (LPC), an atherogenic lipid, we measured ROS production in cultured bovine aortic endothelial cells (BAECs) by the lucigenin-enhanced chemiluminescence (CL) method and electron spin resonance (ESR). BAEC homogenates had the enzymatic activity of NADH/NADPH oxidase. BAECs cultured on microcarrier beads generated O2(-) under basal conditions. The inhibition of NADH/ NADPH oxidase by diphenylene iodonium (DPI) significantly attenuated O2(-) production, whereas no inhibitors of other oxidases suppressed it. Although LPC enhanced O2(-) production approximately 3.1-fold, its action was suppressed by DPI. Tyrosine kinase inhibitors significantly attenuated LPC-induced O2(-) production. ESR with DMPO demonstrated that LPC increased the formation of the DMPO-hydroxyl adduct in dose- and time-dependent manners. These data suggest that the basal production of O2(-) in endothelial cells is mainly mediated by the NADH/NADPH oxidase system and that LPC activates this oxidase to enhance O2(-) production through a tyrosine kinase-dependent pathway. The enhancement of ROS production by LPC is probably involved in its atherogenic property.
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Affiliation(s)
- S Takeshita
- First Department of Internal Medicine, Kobe University School of Medicine, Japan
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376
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Hasdan G, Benchetrit S, Rashid G, Green J, Bernheim J, Rathaus M. Endothelial dysfunction and hypertension in 5/6 nephrectomized rats are mediated by vascular superoxide. Kidney Int 2002; 61:586-90. [PMID: 11849400 DOI: 10.1046/j.1523-1755.2002.00166.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Nitric oxide inactivation by superoxide impairs endothelium-dependent vasodilation and plays a role in various forms of hypertension. Almost no data exist regarding hypertension secondary to chronic renal failure. Previous studies have shown that endothelium-related relaxations, secondary to decreased nitric oxide bioactivity, are impaired in resistance vessels from rats 3 to 10 days after renal mass reduction (RMR). METHODS The membrane-permeable superoxide dismutase (SOD)-mimetic (tempol) was administered IP (1.5 mmol/kg/day for 10 days) to RMR rats and sham-operated controls (SN). Systolic blood pressure (SBP) was measured by tail cuff manometry at days 0, 3, 6 and 10. The increase of flow induced by acetylcholine (10-6 mol/L) was measured in isolated perfused mesenteric arteries from RMR and SN rats pre-contracted with noradrenaline (1 to 5 micromol/L), with or without exogenous SOD. Plasma levels of advanced oxidative protein products (AOPPs; chloramine-T equivalents) were measured in SN and RMR rats. RESULTS Tempol prevented the increase of SBP: 118 +/- 2.2 mm Hg at baseline and 122 +/- 1.6 mm Hg at 10 days in tempol-treated vs 118.14 +/- 1.65 mm Hg at baseline and 145 +/- 7.69 mm Hg at 10 days in untreated RMR rats (P < 0.01). Responsiveness to acetylcholine was reduced in RMR rats (peak flow increase: 139 +/- 7.8% vs. 176 +/- 11% in SN, P=0.028 at 3 days and 140 +/- 6.4% vs. 187 +/- 16.9% in SN at 10 days, P=0.007). In arteries pre-incubated with SOD (200 U/mL) the peak flows were 175 +/- 9.4% at 3 days and 157 +/- 5.8% at 10 days (P=0.007 and P=0.051, respectively, vs. control RMR vessels). AOPP values were significantly increased in plasma from RMR rats 3 days after 5/6 nephrectomy (747 +/- 107 vs. 481 +/- 77 micromol/L, P < 0.05) but returned to normal by day 10. AOPP levels were not significantly reduced by tempol. CONCLUSIONS Increased vascular superoxide production plays a central role in the development of vascular endothelial dysfunction and hypertension early after 5/6 nephrectomy.
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Affiliation(s)
- Galit Hasdan
- Department of Nephrology and Hypertension, Sapir Medical Center, Kfar Saba and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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377
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Wesselman JPM, De Mey JGR. Angiotensin and cytoskeletal proteins: role in vascular remodeling. Curr Hypertens Rep 2002; 4:63-70. [PMID: 11790294 DOI: 10.1007/s11906-002-0055-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Vascular remodeling occurs during normal development and is involved in various physiologic events. However, the adaptive structural changes of the vasculature can also be pathologic, leading to vascular disease such as hypertension, atherosclerosis, and vein graft disease. Pre-eclampsia may develop as a consequence of inappropriate vascular remodeling during pregnancy. Angiotensin II contributes to vascular remodeling by activating signal transduction cascades that promote vasoconstriction, growth, and inflammation. The cytoskeleton also participates in structural adaptation responses of the vasculature; cytoskeletal filaments may mediate vasoactive responses, transduce mechanical stimuli, and are involved in pharmacologic signal transduction. It has become clear that many of the cytoskeletal changes during vascular remodeling can be induced by angiotensin II. Recently, the small G-protein Rho has attracted much attention. The Rho/Rho-kinase system is activated by angiotensin II, is a prominent regulator of the cytoskeleton, and is involved in pathologic vascular remodeling.
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Affiliation(s)
- Jos P M Wesselman
- Department of Pharmacology & Toxicology, Cardiovascular Research Institute Maastricht, Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands.
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378
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Denicola A, Batthyány C, Lissi E, Freeman BA, Rubbo H, Radi R. Diffusion of nitric oxide into low density lipoprotein. J Biol Chem 2002; 277:932-6. [PMID: 11689557 DOI: 10.1074/jbc.m106589200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A key early event in the development of atherosclerosis is the oxidation of low density lipoprotein (LDL) via different mechanisms including free radical reactions with both protein and lipid components. Nitric oxide (( small middle dot)NO) is capable of inhibiting LDL oxidation by scavenging radical species involved in oxidative chain propagation reactions. Herein, the diffusion of ( small middle dot)NO into LDL is studied by fluorescence quenching of pyrene derivatives. Selected probes 1-(pyrenyl)methyltrimethylammonium (PMTMA) and 1-(pyrenyl)-methyl-3-(9-octadecenoyloxy)-22,23-bisnor-5-cholenate (PMChO) were chosen so that they could be incorporated at different depths of the LDL particle. Indeed, PMTMA and PMChO were located in the surface and core of LDL, respectively, as indicated by changes in fluorescence spectra, fluorescence quenching studies with water-soluble quenchers and the lifetime values (tau(o)) of the excited probes. The apparent second order rate quenching constants of ( small middle dot)NO (k(NO)) for both probes were 2.6-3.8 x 10(10) m(-1) s(-1) and 1.2 x 10(10) m(-1) s(-1) in solution and native LDL, respectively, indicating that there is no significant barrier to the diffusion of ( small middle dot)NO to the surface and core of LDL. Nitric oxide was also capable of diffusing through oxidized LDL. Considering the preferential partitioning of ( small middle dot)NO in apolar milieu (6-8 for n-octanol:water) and therefore a larger ( small middle dot)NO concentration in LDL with respect to the aqueous phase, a corrected k(NO) value of approximately 0.2 x 10(10) m(-1) s(-1) can be determined, which still is sufficiently large and consistent with a facile diffusion of ( small middle dot)NO through LDL. Applying the Einstein-Smoluchowsky treatment, the apparent diffusion coefficient (D(')NO) of ( small middle dot)NO in native LDL is on average 2 x 10(-5) cm(2) s(-1), six times larger than that previously reported for erythrocyte plasma membrane. Thus, our observations support that ( small middle dot)NO readily traverses the LDL surface accessing the hydrophobic lipid core of the particle and affirm a role for ( small middle dot)NO as a major lipophilic antioxidant in LDL.
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Affiliation(s)
- Ana Denicola
- Department of Physical Biochemistry, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay
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379
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Cachofeiro Ramos V, de las Heras Jiménez N, Cediel Gil E, Vázquez-Pérez S, Sanz-Rosa D, Oubiña Romeu M, Lahera Juliá V. Papel de la agiotensina II en el desarrollo aterosclerótico: efecto de su bloqueo. HIPERTENSION Y RIESGO VASCULAR 2002. [DOI: 10.1016/s1889-1837(02)71301-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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380
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Fennell JP, Brosnan MJ, Frater AJ, Hamilton CA, Alexander MY, Nicklin SA, Heistad DD, Baker AH, Dominiczak AF. Adenovirus-mediated overexpression of extracellular superoxide dismutase improves endothelial dysfunction in a rat model of hypertension. Gene Ther 2002; 9:110-7. [PMID: 11857069 DOI: 10.1038/sj.gt.3301633] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2001] [Accepted: 11/30/2001] [Indexed: 11/09/2022]
Abstract
Gene transfer may be appropriate for therapeutic protocols targeted at the vascular endothelium. Endothelial dysfunction is the principal phenotype associated with atherosclerosis and hypertension. Oxidative stress has been implicated in the development of endothelial dysfunction. We have explored the ability of overexpressing anti-oxidant genes (superoxide dismutases; SODs) in vitro and in vivo to assess their potential for reversing endothelial dysfunction in a rat model, the stroke-prone spontaneously hypertensive rat (SHRSP). Western blotting and immunofluorescence assays in vitro showed efficient overexpression of MnSOD and ECSOD with respect to localisation to the mitochondria and extracellular surface, respectively. Transgene functional activity was quantified with SOD activity assays. MnSOD and ECSOD overexpression in intact SHRSP vessels in vivo led to endothelial and adventitial overexpression. Pharmacological assessment of transduced vessels following in vivo delivery by basal NO availability quantification demonstrated that the "null" adenovirus and MnSOD adenovirus did not significantly increase NO availability. However, AdECSOD-treated carotid arteries showed a significant increase in NO availability (1.91 +/- 0.04 versus 0.75 +/- 0.08 g/g, n = 6, P = 0.029). In summary, efficient overexpression of ECSOD, but not MnSOD in vivo, results in improved endothelial function in a rat model of hypertension and has important implications for the development of endothelial-based vascular gene therapy.
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Affiliation(s)
- J P Fennell
- BHF Blood Pressure Group, Department of Medicine and Therapeutics, University of Glasgow, Glasgow, UK
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381
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Tan KCB, Chow WS, Ai VHG, Lam KSL. Effects of angiotensin II receptor antagonist on endothelial vasomotor function and urinary albumin excretion in type 2 diabetic patients with microalbuminuria. Diabetes Metab Res Rev 2002; 18:71-6. [PMID: 11921421 DOI: 10.1002/dmrr.255] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Microalbuminuria is associated with dysfunction of the vascular endothelium in patients with diabetes mellitus. The objective of the present study was to determine whether treatment with losartan at a dose sufficient to lower urinary albumin excretion was accompanied by an improvement in endothelial function in type 2 diabetic patients with microalbuminuria. METHODS Endothelial function was measured in 80 type 2 diabetic patients with microalbuminuria and 68 non-diabetic controls using high-resolution vascular ultrasound. The diabetic patients were randomised to receive either losartan 50 mg daily or placebo in a 6-month double-blind study. Urinary albumin excretion and endothelial function were assessed at baseline, 3 and 6 months. RESULTS Both endothelium-dependent (p<0.01) and -independent vasodilation (p<0.01) were significantly impaired in diabetic patients with or without history of hypertension compared to the non-diabetic controls. At baseline, the losartan- and placebo-treated groups were comparable in their clinical characteristics. Blood pressure did not change significantly in either group throughout the study. Urinary mean albumin excretion rate (MAER) decreased in the losartan-treated group (p<0.01) whereas an increase was observed in the placebo group (p<0.05). At 6 months, the losartan-treated group had significantly lower MAER than the placebo-treated group [54.5 (58.3) vs 78.5 (100.5) microg/min, p<0.05; median (interquartile range)]. No significant differences were found in endothelium-dependent or -independent vasodilation. CONCLUSIONS Type 2 diabetic patients with microalbuminuria have impaired endothelium-dependent and -independent vasodilation. Treatment with low-dose losartan is sufficient to reduce microalbuminuria in these patients without alteration in endothelial function and systemic blood pressure.
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Affiliation(s)
- Kathryn C B Tan
- Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China.
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382
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Ferrario CM, Smith R, Levy P, Strawn W. The hypertension-lipid connection: insights into the relation between angiotensin II and cholesterol in atherogenesis. Am J Med Sci 2002; 323:17-24. [PMID: 11814137 DOI: 10.1097/00000441-200201000-00004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Clinical data and experimental studies have established the important role of abnormal lipid metabolism in the causation of atherosclerosis and enthroned the hydroxymethylglutaryl coenzyme reductase inhibitors (statins) as a mainstay in management of patients with coronary heart disease. However, emerging experimental data underline the role of vascular renin-angiotensin systems in mediating the early stages of vascular endothelial dysfunction and inflammation as prerequisites for unleashing the cascade of cellular and molecular events that lead to the deposition of foam cells and their eventual progression to the atherosclerotic plaque. We discuss here the biological effects of statins and angiotensin II in the evolution of atherogenesis, underscoring possible links between statins and angiotensin receptor blockers. From the assessment of the commonality of effects resulting from the nonlipidic actions of statins and angiotensin II on the process of atherogenesis, we develop the argument that dyslipidemia may influence the ability to control blood pressure in hypertensive subjects and hypothesize that the combined use of statins and blockers of the renin-angiotensin system may have an additive effect in the management of hypertensive subjects.
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Affiliation(s)
- Carlos M Ferrario
- Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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383
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Kuramitsu HK, Qi M, Kang IC, Chen W. Role for periodontal bacteria in cardiovascular diseases. ANNALS OF PERIODONTOLOGY 2001; 6:41-7. [PMID: 11887470 DOI: 10.1902/annals.2001.6.1.41] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Several epidemiological studies as well as a recent animal model approach have suggested a role for periodontal diseases in the development of cardiovascular disease (CVD). This relationship could be mediated by inflammatory responses induced by periodontal pathogens as well as direct interaction of these organisms with cardiac tissue. METHODS In order to explore these possibilities, the effects of the periodontal pathogen Porphyromonas gingivalis on cellular events proposed to play a role in CVD were investigated. RESULTS P. gingivalis, as well as its outer membrane vesicles (OMV), was able to induce foam cell formation (an important characteristic of CVD) in the murine macrophage cell line J774 A.1. This property appears to be mediated by the lipopolysaccharide (LPS) fraction of the cells. Several other oral bacteria were also able to induce foam cell formation. Furthermore, since the rupture of the fibrous cap of plaque appears to be an important factor in acute coronary syndrome, it was demonstrated that P. gingivalis 381 degraded fibrous caps isolated from autopsy samples. In addition, it was observed that strain 381 strongly induced matrix metalloproteinase (MMP)-9 protease activity, implicated in plaque rupture, from the J774 A.1 macrophages. Finally, strain 381 was able to enhance monocyte chemoattractant protein-1 (MCP-1) and NADH oxidase expression from endothelial cells. CONCLUSIONS Therefore, P. gingivalis exhibits several properties which could play a role in CVD as mediators of LDL oxidation, foam cell formation, and rupture of atherosclerotic plaque.
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Affiliation(s)
- H K Kuramitsu
- Department of Oral Biology, University at Buffalo, Buffalo, New York, USA
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384
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Trostchansky A, Batthyány C, Botti H, Radi R, Denicola A, Rubbo H. Formation of lipid-protein adducts in low-density lipoprotein by fluxes of peroxynitrite and its inhibition by nitric oxide. Arch Biochem Biophys 2001; 395:225-32. [PMID: 11697860 DOI: 10.1006/abbi.2001.2583] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxynitrite (PN), the product of the diffusion-limited reaction between nitric oxide (*NO) and superoxide (O*-(2)), represents a relevant mediator of oxidative modifications in low-density lipoprotein (LDL). This work shows for the first time the simultaneous action of low-controlled fluxes of PN and *NO on LDL oxidation in terms of lipid and protein modifications as well as oxidized lipid-protein adduct formation. Fluxes of PN (e.g., 1 microM min(-1)) initiated lipid oxidation in LDL as measured by conjugated dienes and cholesteryl ester hydroperoxides formation. Oxidized-LDL exhibited a characteristic fluorescent emission spectra (lambda(exc) = 365 nm, lambda(max) = 417 nm) in parallel with changes in both the free amino groups content and the relative electrophoretic mobility of the particle. Physiologically relevant fluxes of *NO (80-300 nM min(-1)) potently inhibited these PN-dependent oxidative processes. These results are consistent with PN-induced adduct formation between lipid oxidation products and free amino groups of LDL in a process prevented by the simultaneous presence of *NO. The balance between rates of PN and *NO production in the vascular wall will critically determine the final extent of LDL oxidative modifications leading or not to scavenger receptor-mediated LDL uptake and foam cell formation.
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Affiliation(s)
- A Trostchansky
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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385
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Dzau VJ, Bernstein K, Celermajer D, Cohen J, Dahlöf B, Deanfield J, Diez J, Drexler H, Ferrari R, van Gilst W, Hansson L, Hornig B, Husain A, Johnston C, Lazar H, Lonn E, Lüscher T, Mancini J, Mimran A, Pepine C, Rabelink T, Remme W, Ruilope L, Ruzicka M, Schunkert H, Swedberg K, Unger T, Vaughan D, Weber M. The relevance of tissue angiotensin-converting enzyme: manifestations in mechanistic and endpoint data. Am J Cardiol 2001; 88:1L-20L. [PMID: 11694220 DOI: 10.1016/s0002-9149(01)01878-1] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Angiotensin-converting enzyme (ACE) is primarily localized (>90%) in various tissues and organs, most notably on the endothelium but also within parenchyma and inflammatory cells. Tissue ACE is now recognized as a key factor in cardiovascular and renal diseases. Endothelial dysfunction, in response to a number of risk factors or injury such as hypertension, diabetes mellitus, hypercholesteremia, and cigarette smoking, disrupts the balance of vasodilation and vasoconstriction, vascular smooth muscle cell growth, the inflammatory and oxidative state of the vessel wall, and is associated with activation of tissue ACE. Pathologic activation of local ACE can have deleterious effects on the heart, vasculature, and the kidneys. The imbalance resulting from increased local formation of angiotensin II and increased bradykinin degradation favors cardiovascular disease. Indeed, ACE inhibitors effectively reduce high blood pressure and exert cardio- and renoprotective actions. Recent evidence suggests that a principal target of ACE inhibitor action is at the tissue sites. Pharmacokinetic properties of various ACE inhibitors indicate that there are differences in their binding characteristics for tissue ACE. Clinical studies comparing the effects of antihypertensives (especially ACE inhibitors) on endothelial function suggest differences. More comparative experimental and clinical studies should address the significance of these drug differences and their impact on clinical events.
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Affiliation(s)
- V J Dzau
- Department of Medicine, Brigham Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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386
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Sugimoto K, Tsuruoka S, Fujimura A. Effect of enalapril on diabetic nephropathy in OLETF rats: the role of an anti-oxidative action in its protective properties. Clin Exp Pharmacol Physiol 2001; 28:826-30. [PMID: 11553023 DOI: 10.1046/j.1440-1681.2001.03530.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. We have evaluated the effects of the angiotensin-converting enzyme inhibitor enalapril on renal function and oxidative status in the kidney of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of spontaneous onset of type 2 diabetes mellitus. 2. Enalapril (5 mg/kg) or vehicle (distilled water) was given once daily by gavage to 22-week-old male OLETF rats for 32 weeks. Long-Evans Tokushima Otsuka (LETO) rats, the control animals for OLETF rats, received vehicle alone (n = 10 in each group). 3. Enalapril attenuated the rise in blood pressure mildly, but significantly. Enalapril significantly blunted the development of proteinuria without a significant effect on creatinine clearance. At the end of the study period, the lipid peroxide content in the renal cortex was significantly increased in OLETF compared with LETO rats, in which enalapril had no effect on lipid peroxide content. Enalapril enhanced the activity of catalase in the renal cortex of OLETF rats, but had no effect on the activity of either superoxide dismutase or glutathione peroxidase. 4. These results suggest that oxidative stress may be involved in the development of nephropathy in type 2 diabetes. Enalapril exhibited renoprotective effects without changing lipid peroxides in the kidney, suggesting that the beneficial effects of the compound on diabetic renal damage in OLETF rats may not be mediated through an anti-oxidative action.
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Affiliation(s)
- K Sugimoto
- Department of Clinical Pharmacology, Jichi Medical School, Tochigi, Japan. ksugi.jichi.ac.jp
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387
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Affiliation(s)
- B Hornig
- Abteilung Kardiologie und Angiologie, Medizinische Hochschule Hannover, Hannover, Germany.
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388
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Halcox JP, Quyyumi AA. Coronary vascular endothelial function and myocardial ischemia: why should we worry about endothelial dysfunction? Coron Artery Dis 2001; 12:475-84. [PMID: 11696686 DOI: 10.1097/00019501-200109000-00006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- J P Halcox
- Cardiology Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1650, USA
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389
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Takatsu H, Tasaki H, Kim HN, Ueda S, Tsutsui M, Yamashita K, Toyokawa T, Morimoto Y, Nakashima Y, Adachi T. Overexpression of EC-SOD suppresses endothelial-cell-mediated LDL oxidation. Biochem Biophys Res Commun 2001; 285:84-91. [PMID: 11437376 DOI: 10.1006/bbrc.2001.5114] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxygen species have been proposed to play important roles in atherosclerosis. To investigate the protective role of extracellular superoxide dismutase (EC-SOD), its inhibition of endothelial-cell-mediated LDL oxidation was examined. We constructed the recombinant adenovirus AxCAEC-SOD expressing human EC-SOD by CAG promoter. Infection of endothelial cells with AxCAEC-SOD resulted in EC-SOD protein secretion in a dose-dependent manner and a decrease of endothelial-cell-derived superoxide production. Moreover, it was proven to coexist with heparan sulfate by immunohistochemical staining. Endothelial-cell-mediated LDL oxidation enhanced by ferric-sodium EDTA was inhibited by 47% in TBARS formation by AxCAEC-SOD infection. In agarose gel electrophoresis, AxCAEC-SOD decreased the negative charge of oxidized LDL by 50% and suppressed fragmentation of apolipoprotein B. These results suggested that human EC-SOD localized in the extracellular space and reduced endothelial-cell-mediated LDL oxidation. In subendothelial space, EC-SOD bound on heparan sulfate might suppress LDL oxidation through reduction of superoxide anion.
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Affiliation(s)
- H Takatsu
- Second Department of Internal Medicine, Occupational Pneumology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu, Japan
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390
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Li JM, Mullen AM, Shah AM. Phenotypic properties and characteristics of superoxide production by mouse coronary microvascular endothelial cells. J Mol Cell Cardiol 2001; 33:1119-31. [PMID: 11444917 DOI: 10.1006/jmcc.2001.1372] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coronary microvascular endothelial cells exert (patho)physiological effects on the function of cardiac myocytes, which may be studied experimentally using pure cell populations. As an essential pre-requisite to the investigation of cells from gene-modified mice, we studied the phenotypic properties of coronary microvascular endothelial cells isolated from normal mice, and biochemically characterized the superoxide production by these cells. Microvascular endothelial cells were isolated from devitalized mouse ventricular tissue after sequential digestion with collagenase, trypsin and DNase. Coronary microvascular endothelial cells were separated from cardiac myocytes and other cells by differential centrifugation, plating and culture. Mouse coronary microvascular endothelial cells showed an irregular "cobblestone" morphology at confluence, were >98% positive for CD31 by FACS analysis, and were also positive for VE-cadherin and endothelial-type nitric oxide synthase (eNOS) by confocal microscopy. The cells took up fluorescently labelled, acetylated low-density lipoprotein, but were negative for a alpha -smooth muscle actin, desmin and cytokeratin. Unlike human endothelial cells, mouse coronary microvascular endothelial cells only weakly expressed von Willebrand factor. Immunoblotting showed that the mouse cells expressed components of a phagocyte-type NADPH oxidase. They exhibited NADPH-dependent O(2)(-)-generating activity, which was increased by angiotensin II but completely inhibited by diphenyleneiodonium. Thus, mouse coronary microvascular endothelial cells express both eNOS and NADPH oxidase, interactions between which may play a role in endothelial cell pathophysiology.
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Affiliation(s)
- J M Li
- Department of Cardiology, Guy's King's & St Thomas' School of Medicine, King's College London, SE5 9PJ, UK
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391
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Kyaw M, Yoshizumi M, Tsuchiya K, Kirima K, Tamaki T. Antioxidants inhibit JNK and p38 MAPK activation but not ERK 1/2 activation by angiotensin II in rat aortic smooth muscle cells. Hypertens Res 2001; 24:251-61. [PMID: 11409648 DOI: 10.1291/hypres.24.251] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Angiotensin II (Ang II) induces vascular smooth muscle cell (VSMC) hypertrophy, which results in several cardiovascular diseases. Ang II-induced cellular events have been mediated, in part, by reactive oxygen species (ROS) which also involve activation of mitogen-activated protein (MAP) kinases. Although it has been proposed that the therapeutic administration of antioxidants is useful for vascular diseases, the precise mechanisms which regulate ROS-sensitive signaling events have not been well characterized. Thus, we hypothesized that antioxidants may affect ROS-mediated MAP kinases activation induced by Ang II. The present findings showed that Ang II stimulated rapid and significant activation of ERK 1/2, JNK and p38 MAPK in cultured rat aortic smooth muscle cells (RASMC). Ang II-induced ERK 1/2 activation was not affected by all antioxidants examined, whereas JNK was sensitive to all antioxidants. In contrast, p38 MAPK activation was inhibited by DPI and ascorbic acid concentration-dependently, but by NAC only at high concentration. DETC and Trolox C had no effects on p38 MAPK activation by Ang II. We further examined the effects of antioxidants on Ang II-induced increases in oxygen consumption as an index of ROS generation in RASMC. DPI strongly inhibited Ang II-induced increases in oxygen consumption. DETC also inhibited Ang II-induced oxygen consumption, whereas ascorbic acid markedly augmented it. These findings suggest that the inhibitory effects of antioxidants on MAP kinases activation in VSMC are attributable, in part, to their modulating effects on ROS generation by Ang II in VSMC. Thus, inhibition of MAP kinases by antioxidants may imply their usefulness for relief of cardiovascular diseases.
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MESH Headings
- Acetylcysteine/pharmacology
- Angiotensin II/pharmacology
- Animals
- Antioxidants/pharmacology
- Aorta, Thoracic/cytology
- Ascorbic Acid/pharmacology
- Cells, Cultured
- Chelating Agents/pharmacology
- Chromans/pharmacology
- Ditiocarb/pharmacology
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Free Radical Scavengers/pharmacology
- JNK Mitogen-Activated Protein Kinases
- MAP Kinase Kinase 4
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/physiology
- Male
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Onium Compounds/pharmacology
- Oxygen Consumption/drug effects
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Vasoconstrictor Agents/pharmacology
- p38 Mitogen-Activated Protein Kinases
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Affiliation(s)
- M Kyaw
- Department of Pharmacology, The University of Tokushima School of Medicine, Japan
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392
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Rösen P, Nawroth PP, King G, Möller W, Tritschler HJ, Packer L. The role of oxidative stress in the onset and progression of diabetes and its complications: a summary of a Congress Series sponsored by UNESCO-MCBN, the American Diabetes Association and the German Diabetes Society. Diabetes Metab Res Rev 2001; 17:189-212. [PMID: 11424232 DOI: 10.1002/dmrr.196] [Citation(s) in RCA: 624] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review summarises the results and discussions of an UNESCO-MCBN supported symposium on oxidative stress and its role in the onset and progression of diabetes. There is convincing experimental and clinical evidence that the generation of reactive oxygen species (ROI) is increased in both types of diabetes and that the onset of diabetes is closely associated with oxidative stress. Nevertheless there is controversy about which markers of oxidative stress are most reliable and suitable for clinical practice. There are various mechanisms that contribute to the formation of ROI. It is generally accepted that vascular cells and especially the endothelium become one major source of ROI. An important role of oxidative stress for the development of vascular and neurological complications is suggested by experimental and clinical studies. The precise mechanisms by which oxidative stress may accelerate the development of complications in diabetes are only partly known. There is however evidence for a role of protein kinase C, advanced glycation end products (AGE) and activation of transcription factors such as NF kappa B, but the exact signalling pathways and the interactions with ROI remain a matter of discussion. Additionally, results of very recent studies suggest a role for ROI in the development of insulin resistance. ROI interfere with insulin signalling at various levels and are able to inhibit the translocation of GLUT4 in the plasma membrane. Evidence for a protective effect of antioxidants has been presented in experimental studies, but conclusive evidence from patient studies is missing. Large-scale clinical trials such as the DCCT Study or the UKPDS Study are needed to evaluate the long-term effects of antioxidants in diabetic patients and their potential to reduce the medical and socio-economic burden of diabetes and its complications.
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Affiliation(s)
- P Rösen
- Deutsches Diabetesforschungsinstitut, Düsseldorf, Germany.
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393
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Abstract
CS-866 is a new angiotensin II receptor blocker that has demonstrated effectiveness for lowering blood pressure in animal models of hypertension. Given the proposed involvement of the renin-angiotensin system in diabetic nephropathy and atherosclerosis, we have tested CS-866 in animal models of these conditions. The renal protective properties of CS-866 were examined in the Zucker diabetic fatty (ZDF) rat, a model of type 2 diabetes that develops progressive hyperglycemia, glomerulosclerosis, and proteinuria. Treatment of ZDF rats with CS-866 in the diet for 19 weeks resulted in a dose-dependent reduction in urinary protein excretion compared with vehicle-treated control rats, which was independent of changes in blood pressure and glycemic state. The antiatherosclerotic properties of CS-866 were tested in 2 animal models. In the first study, cynomolgus monkeys were fed a high-cholesterol diet for 6 months while receiving CS-866 or vehicle. At the end of this period, CS-866-treated animals had 64% less plaque area in the aorta than controls. CS-866 was also tested in the Watanabe heritable hyperlipidemic (WHHL) rabbit model of atherosclerosis. WHHL rabbits were treated for 32 weeks with CS-866 (1 mg/kg), pravastatin (50 mg/kg), a combination of the 2 drugs, or vehicle. CS-866 had no effect on plasma cholesterol levels and reduced blood pressures minimally. Pravastatin alone reduced serum cholesterol but had no effect on blood pressure or lesion area. In contrast, treatment with CS-866 resulted in a 40% reduction in lesion area compared with vehicle-treated control when given alone and a 50% reduction in combination with pravastatin. On the basis of results from animal models, CS-866 may be a useful treatment for diabetic nephropathy and atherosclerosis.
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Affiliation(s)
- H Koike
- Pharmacology and Molecular Biology Research Laboratories, Sankyo Company, Limited, Tokyo, Japan
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394
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Arakawa K. Pressure, platelets, and plaque: the central role of angiotensin II in cardiovascular pathology. Introduction. Am J Cardiol 2001; 87:1C-2C. [PMID: 11334761 DOI: 10.1016/s0002-9149(01)01508-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- K Arakawa
- Department of Internal Medicine, Fukuoka University School of Medicine, Japan
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395
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Abstract
Numerous clinical and laboratory data are now available supporting the hypothesis that the renin-angiotensin system is mechanistically relevant in the pathogenesis of atherosclerosis. The traditional role of the renin-angiotensin system in the context of blood pressure regulation has been modified to incorporate the concept that angiotensin II (Ang II) is a potent proinflammatory agent. In vascular cells, Ang II is a potent stimulus for the generation of reactive oxygen species. As a result, Ang II upregulates the expression of many redox-sensitive cytokines, chemokines, and growth factors that have been implicated in the pathogenesis of atherosclerosis. Extensive data now confirm that inhibition of the renin-angiotensin system inhibits atherosclerosis in animal models as well as in humans. These studies provide mechanistic insights into the precise role of Ang II in atherosclerosis and suggest that pharmacologic interventions involving the renin-angiotensin system may be of fundamental importance in the treatment and prevention of atherosclerosis.
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Affiliation(s)
- D Weiss
- Department of Medicine, Division of Cardiology, Emory University School of Medicine and The Atlanta Veterans Affairs Medical Center, Atlanta, Georgia 30322, USA
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396
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Abstract
Hypertension is associated with a number of adverse morphologic and functional changes in the cardiovascular system. These include remodeling of the left ventricle, alterations in the morphology and mechanical properties of the vasculature, and the development of endothelial dysfunction. Recent studies have shown that angiotensin II is capable of mediating these changes via its interaction with the angiotensin II type 1 receptor. These nonhemodynamic effects of angiotensin II are independent of its effect on blood pressure. Thus, elevated levels of angiotensin II may lead directly to many hypertension-associated pathologies. Recent evidence that mechanical strain, oxidized low-density lipoprotein cholesterol, and aldosterone can cause upregulation of angiotensin II type 1 receptors indicates that activation of the renin-angiotensin system is not necessary for the actions of angiotensin II to be amplified. Because the strain on the vessel wall may be increased under conditions of hypertension, increased arterial pressure may amplify the actions of angiotensin II without a discernible increase in plasma angiotensin II levels. In both the myocardium and the peripheral vasculature, fibrosis is a major component of the remodeling that occurs in hypertension. There is substantial evidence that transforming growth factor beta-1 (TGF-beta(1)) mediates angiotensin-II-induced fibrosis in patients with hypertension and in those with a variety of nephropathies. Mechanical strain also induces fibrosis in a mechanism mediated by TGF-beta(1). This cytokine thus represents a common pathway by which angiotensin II and increased arterial pressure may induce cardiovascular fibrosis.
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Affiliation(s)
- B Williams
- Cardiovascular Research Institute, Leicester University Medical School, Leicester, UK
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397
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Abstract
Activation of the renin-angiotensin-aldosterone system is associated with unsatisfactory outcomes in patients with hypertension and congestive heart failure, in that activation of this system is correlated strongly with both the incidence and extent of end-organ damage. Despite the availability of the angiotensin-converting enzyme inhibitors and the AT1 receptor antagonists, unblocked aldosterone levels remain an important risk factor for cardiovascular disease progression. New preclinical data generated over the past few years strongly support the hypothesis that aldosterone has important deleterious effects on the cardiovascular system independent of the classical action of this hormone on renal epithelial cells. The new selective aldosterone receptor antagonist eplerenone has been shown to produce significant cardioprotective effects in experimental models of cardiovascular disease. Early clinical testing suggests that eplerenone may have important therapeutic benefit in the treatment of hypertension and heart failure.
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Affiliation(s)
- E G McMahon
- Pharmacia Corporation, St Louis, Missouri 63167, USA.
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398
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John S, Delles C, Jacobi J, Schlaich MP, Schneider M, Schmitz G, Schmieder RE. Rapid improvement of nitric oxide bioavailability after lipid-lowering therapy with cerivastatin within two weeks. J Am Coll Cardiol 2001; 37:1351-8. [PMID: 11300446 DOI: 10.1016/s0735-1097(01)01128-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES We investigated whether improvement of endothelial dysfunction in hypercholesterolemia can be achieved with short-term lipid-lowering therapy. BACKGROUND Impaired endothelium-dependent vasodilation plays a pivotal role in the pathogenesis of atherosclerosis and acute coronary syndromes. METHODS In a randomized, double-blind, placebo-controlled trial, we studied 37 patients (52 +/- 11 yrs) with low density lipoprotein cholesterol > or = 160 mg/dl (196 +/- 44 mg/dl) randomly assigned to either cerivastatin (0.4 mg/d) or placebo. Endothelium-dependent vasodilation of the forearm vasculature was measured by plethysmography and intra-arterial infusion of acetylcholine (ACh 12, 48 microg/min) and endothelium-independent vasodilation by intra-arterial infusion of nitroprusside (3.2, 12.8 microg/min). RESULTS Low density lipoprotein cholesterol decreased after two weeks of treatment (cerivastatin -33 +/- 4% vs. placebo + 2 +/- 4%, x +/- SEM, p < 0.001). Endothelium-dependent vasodilation improved after two weeks of therapy with cerivastatin compared with baseline (ACh 12 microg/min: + 22.3 +/- 5.2 vs. + 11.2 +/- 1.9 ml/min/100 ml, p < 0.01; ACh 48 microg/min: +31.2 +/- 6.3 vs. +19.1 +/- 3.1 ml/min/100 ml, p < 0.05). In contrast, changes in forearm blood flow to ACh were similar before and after therapy in the placebo group (ACh 12 microg/min: + 12.9 +/- 3.6 vs. + 9.0 +/- 1.9 ml/min/100 ml, NS; ACh 48 microg/min: +20.7 +/- 3.7 vs. 19.4 +/- 2.9 ml/min/100 ml, NS). Endothelium-dependent vasodilation improved in comparison with placebo (ACh 48 microg/min: +203 +/- 85% [cerivastatin] vs. -26 +/- 71% [placebo], p < 0.05). This improvement in endothelium-dependent vasodilation was no longer observed when the nitric oxide-synthase inhibitor N(G)-monomethyl-L-arginine was coinfused (ACh 48 microg/min + N(G)-monomethyl-L-arginine 4 micromol/min -48 +/- 85% [cerivastatin]). CONCLUSIONS Short-term lipid-lowering therapy with cerivastatin can improve endothelial function and NO bioavailability after two weeks in patients with hypercholesterolemia.
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Affiliation(s)
- S John
- Department of Medicine IV, University of Erlangen-Nürnberg, Klinikum Nürnberg-Süd, Nürnberg, Germany
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399
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Sorescu D, Somers MJ, Lassègue B, Grant S, Harrison DG, Griendling KK. Electron spin resonance characterization of the NAD(P)H oxidase in vascular smooth muscle cells. Free Radic Biol Med 2001; 30:603-12. [PMID: 11295358 DOI: 10.1016/s0891-5849(00)00507-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Endogenously produced reactive oxygen species are important for intracellular signaling mechanisms leading to vascular smooth muscle cell (VSMC) growth. It is therefore critical to define the potential enzymatic sources of ROS and their regulation by agonists in VSMCs. Previous studies have investigated O2*- production using lucigenin-enhanced chemiluminescence. However, lucigenin has been recently criticized for its ability to redox cycle and its propensity to measure cellular reductase activity independent from O2*-. To perform a definitive characterization of VSMC oxidase activity, we used electron spin resonance trapping of O2*- with DEPMPO. We confirmed that the main source of O2*- from VSMC membranes is an NAD(P)H oxidase and that the O2*- formation from mitochondria, xanthine oxidase, arachidonate-derived enzymes, and nitric oxide synthases in VSMC membranes was minor. The VSMC NAD(P)H oxidase(s) are able to produce more O2*- when NADPH is used as the substrate compared to NADH (the maximal NADPH signal is 2.4- +/- 0.4-fold higher than the NADH signal). The two substrates had similar EC(50)'s ( approximately 10-50 microM). Stimulation with angiotensin II and platelet-derived growth factor also predominantly increased the NADPH-driven signal (101 +/- 8% and 83 +/- 1% increase above control, respectively), with less of an effect on NADH-dependent O2*- (17 +/- 3% and 36 +/- 5% increase, respectively). Moreover, incubation of the cells with diphenylene iodonium inhibited predominantly NADPH-stimulated O2*-. In conclusion, electron spin resonance characterization of VSMC oxidase activity supports a major role for an NAD(P)H oxidase in O2*- production in VSMCs, and provides new evidence concerning the substrate dependency and agonist-stimulated activity of this key enzyme.
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MESH Headings
- Acridines/metabolism
- Angiotensin II/pharmacology
- Animals
- Cell Membrane/drug effects
- Cell Membrane/enzymology
- Cell Membrane/metabolism
- Cells, Cultured
- Cyclic N-Oxides/metabolism
- Electron Spin Resonance Spectroscopy
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- NAD/metabolism
- NADP/metabolism
- NADPH Oxidases/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Spin Labels
- Substrate Specificity
- Superoxides/metabolism
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Affiliation(s)
- D Sorescu
- Department of Medicine, Division of Cardiology, Emory University, Atlanta, GA 30322, USA
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400
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Souza HP, Laurindo FR, Ziegelstein RC, Berlowitz CO, Zweier JL. Vascular NAD(P)H oxidase is distinct from the phagocytic enzyme and modulates vascular reactivity control. Am J Physiol Heart Circ Physiol 2001; 280:H658-67. [PMID: 11158964 DOI: 10.1152/ajpheart.2001.280.2.h658] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An NAD(P)H oxidase has been hypothesized to be the main source of reactive oxygen species (ROS) in vessels; however, questions remain about its function and similarity with the neutrophil oxidase. Therefore, vascular superoxide generation was measured by electron paramagnetic resonance spectroscopy using the spin-trap 5,5'-dimethly-pyrroline-N-oxide in aortas from wild-type (WT) and gp91(phox)-deficient mice (gp91(phox)-/-), which do not have a functioning neutrophil NADPH oxidase. There was no significant difference between radical adduct formation by WT or gp91(phox)-/- mouse aortas either at baseline or after stimulation with NADPH or NADH. Also, spin-adduct formation was identical in the 100,000-g pellets obtained from WT and gp91(phox)-/- mouse aortas. SOD mimetics and the flavoenzyme inhibitor diphenyleneiodonium blocked spin-adduct formation from both intact vessels and particulate fractions. Other pharmacological inhibitors of metabolic pathways involved in ROS generation had no effect on this phenomenon. To examine the role of this enzyme in vascular tone control, aortic rings were suspended in organ chambers and preconstricted with phenylephrine to reach half-maximal contraction. Exposure to NADPH elicited a 20% increase in vascular tone, which was decreased by SOD mimetics in a concentration-dependent manner, suggesting that superoxide was responsible for this phenomenon. NADH had no effect on vascular tone. Thus superoxide is generated in the vessel wall by an NAD(P)H-dependent oxidase, which modulates vascular contractile tone. This enzyme is structurally and genetically distinct from the neutrophil NADPH oxidase.
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Affiliation(s)
- H P Souza
- Molecular and Cellular Biophysics Laboratories and the Electron Paramagnetic Resonance Center, Cardiology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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