17-Estradiol Attenuates Development of Angiotensin II– Induced Aortic Abdominal Aneurysm in Apolipoprotein E– Deficient Mice Baby Martin-McNulty, Doris M. Tham, Valdeci da Cunha, Jerrick J. Ho, Dennis W. Wilson, John C. Rutledge, Gary G. Deng, Ronald Vergona, Mark E. Sullivan, Yi-Xin Wang Objectives—Angiotensin II (Ang II) promotes vascular inflammation, accelerates atherosclerosis, and induces abdominal aortic aneurysm (AAA). These changes were associated with activation of nuclear factor (NF)-B–mediated induction of proinflammatory genes. The incidence of AAA in this model was higher in male than in female mice, and the vascular effects of estrogen may be associated with anti-inflammatory actions. The present study was undertaken to test the hypothesis that estrogen can attenuate Ang II–induced AAA in apolipoprotein E– deficient mice via its antiinflammatory mechanism. Methods and Results—Infusion of Ang II (1.44 mg/kg per d for 1 month) induced AAA in 90% of the animals (n⫽20) with an expansion of the suprarenal aorta (diameter 1.9⫾0.14 mm versus ⬍1 mm in normal mice). In mice treated with 17-estradiol (E2, 0.25-mg subcutaneous pellets), Ang II induced AAA only in 42% of the animals (n⫽19) with a significant reduction of average diameters of the suprarenal aorta (1.5⫾0.14 mm). E2 also decreased the expressions of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, E-selectin, monocyte chemotactic protein-1, and macrophage-colony stimulating factor in the aorta. Conclusions—These data suggest that attenuation of AAA by E2 is associated with inhibition of proinflammatory gene expression. (Arterioscler Thromb Vasc Biol. 2003;23:1627-1632.) Key Words: estrogen 䡲 aneurysm 䡲 vascular inflammation 䡲 PPAR 䡲 gene expression
A
therosclerosis is an inflammatory disease.1 Infiltration of monocytes and macrophages into the vessel wall is a major source of proteolytic enzymes, including metalloproteinases, which degrade extracellular matrix, thus impairing the integrity of the artery wall and causing aneurysm.2 Angiotensin II (Ang II) has been implicated in vascular inflammation and progression of atherosclerosis.3,4 Chronic infusion of Ang II in apolipoprotein E– deficient (apoE-KO) mice induces aneurysm.5 We demonstrated that vascular inflammation and aneurysm induced by Ang II were associated with activation of nuclear transcription factor (NF)-B– mediated proinflammatory gene induction.6,7 It has been reported clinically that the incidence of abdominal aortic aneurysm (AAA) was higher in males than in females.8 Ang II–induced AAA was also higher in male than in female mice in this model.9 Estrogen has long been recognized to have vascular actions.10 Treatment with estrogen reduces atherosclerotic lesion formation in several animal models, including apoE-KO mice,11,12 even in the absence of lipid-lowering effects.13 Accumulating evidence suggests that
the antiatherosclerotic effects of estrogen can be attributed, at least in part, to anti-inflammatory actions.14,15 Furthermore, there is in vivo evidence that estrogen inhibits the NF-B pathway, which contributes to anti-inflammatory actions.16 The present study, therefore, was aimed to test the hypothesis that treatment of 17-estradiol can attenuate Ang II– induced AAA in apoE-KO mice via the mechanism of inhibiting NF-B–mediated proinflammatory gene induction.
Methods Male apoE-KO mice (Jackson Laboratory, Bar Harbor, Maine) were fed normal rodent chow. When the mice were 5 months old, a 17 -estradiol pellet (0.25 mg/pellet, 60-day release, IRA) was implanted subcutaneously (E2). A separate group of age-matched apoE-KO mice with no E2 implantation was used as control. According to the data provided by the manufacturer, this dose of E2 can reach blood concentration of 100 to 150 pg/mL, a level well within the physiological range in women before ovulation.17 After 30 days, when the animals were 6 months old, an osmotic mini-pump (Alzet, model 2004) containing Ang II (1.44 mg/kg per d) was implanted subcutaneously in both the E2 and control groups. Thirty days after mini-pump implantation, blood pressure and heart rate were measured noninvasively in conscious animals by the tail-cuff
Received May 29, 2003; revision accepted June 30, 2003. From the Department of Pharmacology (B.M.-M., V.d.C., J.H.J., R.V., M.E.S., Y.-X.W.) and Cardiovascular Research (G.C.D.), Berlex Biosciences, Richmond, and Department of Internal Medicine, School of Medicine (D.M.T., J.C.R.) and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine (D.W.W.), University of California at Davis, Calif. Correspondence to Yi-Xin Wang, Department of Pharmacology, Berlex Biosciences, 2600 Hilltop Rd, PO Box 4099, Richmond, CA 94806. E-mail
[email protected] © 2003 American Heart Association, Inc. Arterioscler Thromb Vasc Biol. is available at http://www.atvbaha.org
DOI: 10.1161/01.ATV.0000085842.20866.6A
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method as described previously.7 The animals were then euthanized. Blood samples were collected via cardiac puncture for the measurement of serum cholesterol profile (IDEXX Veterinary Services). In separate groups of age-matched apoE-KO mice treated with vehicle or Ang II with or without E2 as described above, total blood leukocyte count was determined using an automated hematology analyzer (Baker 9120, BioChem ImmunoSystems Inc). The outer diameter of the suprarenal region was measured from the image captured by a calibrated digital camera attached to a microdissecting microscope as described in detail previously.7 The severity of the aneurysms was subjectively accessed using a 4-grade scoring system based on gross appearance of the aorta as described in detail by Daugherty et al.18 Criteria were as follows: type 0 indicated no aneurysm, with the suprarenal region of the aorta not obviously different from naive apoE-KO mice without Ang II treatment; type I, dilated lumen with no thrombus; type II, remodeled tissue that frequently contained thrombus; type III, a pronounced bulbous form of type II that contained thrombus; and type IV, a form in which there were multiple aneurysms containing thrombus. The left and right carotid arteries were dissected for quantification of atherosclerotic lesion area as described in detail previously7,19 and in the online data supplement (available at http://atvb.ahajournals. org). A transverse section of the suprarenal aorta was excised for immunochemical staining with an antimacrophage antibody (MAC-3; BD Pharmingen) and counterstained with hematoxylin. Rabbit IgG was used as a negative control (Sigma Chemical). To determine the extent of elastolysis and collagen content, adjacent cross-sections of the same aorta were stained with H&E, elastin-Van Giessen, and trichrome. As described in detail previously6 and in the online data supplement, expressions of aortic mRNAs for intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM1), endothelial-selectin (E-selectin), monocyte chemotactic protein-1 (MCP-1), macrophage-colony stimulating factor (M-CSF), PPAR-␣, and PPAR-␥ were determined by real-time polymerase chain reaction. NF-B activity was measured by electrophoretic mobility shift assay from the nuclear extracts of aortic tissue. Nuclear extracts isolated from individual aorta were pooled as 2 samples: control (n⫽5) and E2 (n⫽5). The aortic nuclear extracts from an additional 5 age-matched naive apoE-KO mice without any treatment were used for the measurement of baseline activities of the transcription factors. Using the Myria protein/DNA array kit (Panomics), a set of biotin-labeled DNA-binding oligonucleotides were preincubated with aortic nuclear extracts to allow the formation of DNA/protein complexes. The DNA/protein complexes were then extracted and hybridized to the MYRIA array that contained 54 consensus-binding sequences corresponding to a specific eukaryotic transcription factor. Detection of signals was quantified using the Kodak Electrophoresis Documentation & Analysis System 290 (Eastman Kodak) and normalized to biotinylated DNA spotted on each array. A percent change of activated transcription factors over baseline was compared between the Ang II–infused apoE-KO mice treated with (E2) or without estrogen (control). All experiments were performed in duplicate. Results are presented as mean⫾SEM for the number of animals indicated. Comparison between 2 groups with different treatments was performed by Student’s t test. The percent of mice that developed AAA was compared between 2 groups using 2 test. The differences were considered statistically significant when P⬍0.05.
Figure 1. Atherosclerotic lesion area (top) and systolic blood pressure (bottom) in Ang II–infused apoE-deficient mice treated with (E2) or without (control) 17-estradiol.
E2 with Ang II additionally decreased circulating leukocytes to 4688⫾468 per L (n⫽8), which, however, is not statistically different from mice treated with Ang II only.
17-Estradiol Attenuated Angiotensin II–Induced Aneurysm Formation in ApoE-KO Mice In the control group, infusion of Ang II induced AAA in 90% of the apoE-KO mice (n⫽20). Treatment with E2 significantly reduced Ang II–induced AAA to 42% (n⫽19). Consequently, the average outer diameter of the suprarenal aorta was significantly smaller in the E2 than control group (Figure 2, top). In the E2-treated mice that still developed AAA, the severity (category score) of the aneurysm appeared to be less than in the control group (Figure 2, bottom).
Results Treatment of E2 significantly reduced atherosclerotic lesion area in the carotid arteries by 75% compared with controls (Figure 1, top). Systolic blood pressure was not significantly different between the 2 groups (Figure 1, bottom). There were no significant differences in body weight or cholesterol profiles between the control and E2 groups (see online Table I). Ang II treatment significantly decreased the circulating leukocytes (7450⫾1088 per L, n⫽10) compared with the mice treated with vehicle only (12040⫾1254 per L, n⫽10). Combination of
Figure 2. Average diameters of the suprarenal aorta (top) and classification of aneurysm type (bottom) in angiotensin II–infused apoE-deficient mice treated with (E2) or without (control) 17-estradiol.
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Figure 3. Histological appearance of the suprarenal aortas from a naive (without any treatment) or angiotensin II–infused apoE-KO mice treated with (E2) or without (control) 17-estradiol.
Histological evaluation of the arteries from naive mice showed intact endothelium overlying an intact internal elastic lamina (Figure 3). The modest media had little collagen and was invested with concentric layers of elastin. The adventitia was relatively thin and composed of woven bands of collagen. Control mice treated with Ang II had thick walls with intimal plaques, irregular media, and prominent adventitia. The intima was occasionally disrupted by plaques of Mac-3–positive foam cells on the luminal side of the internal elastic lamina. The thickness of the media was increased by extracellular matrix that was deposited between smooth muscle bundles and stained with trichrome as collagen. Elastin fibers in the media were discontinuous and irregularly oriented (Figure 3 and online Figure I). The adventitia was markedly thickened by extracellular matrix that was predominately collagen. A modest increase in adventitial cellularity included fibroblasts and Mac-3–positive mononuclear cells. Segmental regions of arterial wall had replacement of the media and adventitia by thick bands of fibroblasts in a collagenous matrix. Aortas from E2-treated animals were thicker than naive animals but had fewer intimal plaques and no evidence of macrophage accumulation in the intima. These vessels did have medial changes including collagen deposition and some increase in elastin fibers, but the internal elastic lamina generally remained intact and retained a distinctive media of smooth muscle. The adventitia was thickened by collagen and Mac-3–positive cells to an extent similar to that in the control animals.
17-Estradiol Decreased NF-B–Mediated Proinflammatory Gene Expression and Upregulated PPAR Gene Expression in the Aortic Wall Electrophoretic mobility shift assay detected a 31% decrease in NF-B activity in the E2 group compared with that of the control group (Figure 4, top and middle). However, it did not reach statistical significance. DNA/protein binding array detected a 27% to 60% increase in transcription factor activation, including activator protein-2 (AP-2), Ets, murine embryonic fibroblast-1 (Mef-1), c-Myb, early growth response protein (Egr), NF-E2,
specificity protein-1 (Sp-1), and cAMP-responsive element binding protein (CREB) in the control apoE-KO mice only treated with Ang II compared with the age-matched naive apoE-KO mice without any treatment (Figure 4, bottom). Treatment with E2 reversed the stimulatory effects of Ang II on these transcription factors, which was accompanied by a significant decrease in the expression of proinflammatory genes, including ICAM-1, VCAM-1, E-selectin, MCP-1, and M-CSF in the
Figure 4. Activities of NF-B measured by electrophoric mobility shift assay (an original image on top panel and average values in middle panel) along with other transcriptional factors (bottom) measured by DNA/protein binding array from the aortic nuclear extracts of angiotensin II–infused apoE-KO mice pretreated with (E2) or without (control) 17-estradiol. The DNA/protein binding assay were carried out in pooled samples obtained from 5 mice for each group, and the data were expressed as percent change over age-matched naive apoE-KO mice without any treatment.
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Figure 5. Expression of the proinflammatory cell adhesion molecules ICAM-1, VCAM-1, and E-selectin and chemokines MCP-1 and M-CSF in the suprarenal aorta (top) and other region of the aorta (bottom) from the angiotensin II–infused apoE-KO mice pretreated with (E2) or without (control) 17-estradiol. P⬍0.05 between the 2 groups.
suprarenal aorta (Figure 5, top), where aneurysm was consistently localized, as well as in the other regions of the aorta (Figure 5, bottom). In contrast, the expression of both PPAR-␣ and PPAR-␥ was significantly increased in all sections of the aorta from the E2 group compared with that from the controls (online Figure II).
Discussion The present results demonstrated that treatment of estradiol significantly reduced the incidence and severity of Ang II–induced AAA and atherosclerosis in apoE-KO mice. These effects were associated with a downregulation of the expression of several NF-B– dependent proinflammatory mediators, including ICAM-1, VCAM-1, E-selection, MCP-1, and M-CSF in the aorta. E2 treatment also upregulated the expression of PPAR-␣ and -␥ in the aorta, which may contribute to the anti-inflammatory effects of estrogen. Impairment of the integrity of the artery wall is a major pathological change in aneurysm formation.2 Indeed, histological examination of the aneurysmal tissue from apoE-KO mice infused with Ang II revealed multifocal destruction of the internal elastic lamina, which was prevented by E2 treatment. This result is consistent with our previous observation in which treatment with E2 was also found to protect the elastic lamina from degradation in apoE-KO mice treated with streptozotocin to induce diabetes mellitus.11 Thus, protection of elastic lamina from destruction in the aortic wall by E2 may contribute to the reduction of aneurysm induced by Ang II in apoE-KO mice.
Our previous study demonstrated that treatment of Ang II in apoE-KO mice upregulated the expression of several proinflammatory genes in the aortic wall, including ICAM-1, VCAM-1, E-selectin, MCP-1, and M-CSF.6 The induction of these proinflammatory genes is mediated predominantly by the activation of the NF-B signaling pathway.20 The transcriptional regulation of NF-B involves physical interaction with other transcription factors, such as Sp-1, CREB, and Egr-1.21 Many stimuli associated with the development of vascular disease, including Ang II, are capable of inducing these transcription factors.3,22,23 Once activated, the transcription factors NF-B, Egr-1, and Sp-1 bind to recognition elements in the promoter region of proinflammatory genes and act as dominant regulators of transcription of these genes to induce inflammation.24 Estrogen has long been recognized, although controversially, as a cardiovascular protective agent.10 In many studies, estrogen has been shown to reduce atheroma formation.11,12,25 The present study demonstrated that treatment of E2 significantly reduced atherosclerotic lesions in apoE-KO mice infused with Ang II. It has been shown that estrogen inhibits monocyte adhesion, decreases VCAM-1 and MCP-1 expression in hypercholesterolemic rabbits,14,15 and reduces plasma levels of adhesion molecules and other markers of endothelial activation in postmenopausal women.26,27 Other studies have demonstrated that the inhibition of VCAM-1 expression by estrogen in cultured endothelial cells is through the interference of NF-B activity,28 probably involving inhibition of DNA binding,29 induction of inhibitory B (IB), a natural inhibitor of NF-B, or coactivator sharing.30,31 Furthermore, Evans et al16 demonstrated in vivo reciprocal antagonism between estrogen receptors and NF-B activity, suggesting that the anti-inflammatory benefits of estrogen may be attributable to its ability to interfere with NF-B– mediated inflammatory gene activation in the vasculature. In support of this view, the present data demonstrated that attenuation of Ang II–induced AAA and atherosclerosis by E2 was associated with the inhibition of NF-B, Sp-1, and Egr-1 activities and downregulation of proinflammatory genes. Using DNA/protein binding array technology, the present study also demonstrated that Ang II treatment in apoE-KO mice activated several transcription factors, including AP-2, Ets, Mef-1, c-Myb, Egr, NF-E2, Sp-1, and CREB. These transcription factors may be related to vascular inflammation, atherosclerosis, and aneurysm formation. For example, it has been shown that Egr may play a key regulatory role by linking injurious stimuli, including Ang II, to induce proinflammatory genes that ultimately result in vascular pathology.32,33 CREB has been shown to induce Ang II type 1 receptors, IL-6, COX-2, and VEGF, promote thrombin-induced smooth muscle proliferation, and function as a mediator of growth factor signals.34 In addition, Sp-1, Ets, Ap-1, and Ap-2 have been shown to induce uPA and its receptors and metalloproteinases.35,36 These matrix-degrading proteases are involved in aneurysm formation.2,7 Consistent with these reports, the present study also demonstrated that E2 treatment inhibited the activities of the above transcription factors, sug-
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gesting that this mechanism may also contribute to the effects of E2 in attenuating atherosclerosis development and AAA formation in this model. Accumulating evidence suggests that estrogen directly inhibit the growthpromoting effects of renin-angiotensin system in vascular smooth muscle cells.37 This mechanism could also contribute to the protective effects of estrogen on neointima formation in response to Ang II. The cardiovascular protective effects of estrogen also include several other aspects. For example, estrogen has been shown to decrease blood pressure in hypertensive animals.10,38 Although blood pressure changes could contribute to AAA formation, it was not the case in the present study because blood pressure was not significantly different between the control and E2 groups. It is interesting that the increased expression of proinflammatory genes by Ang II reported in our previous study6 and the suppressive effect of E2 on the expression of these genes in the present study did not vary between different regions of the aorta. However, aneurysm is consistently localized in the suprarenal region in this model. Although the exact mechanism is still unclear, we speculate that when blood flow passes from the thoracic aorta (with negative pressure extravascularly) to the abdominal aorta (with positive pressure extravascularly), the flow becomes more turbulent in the suprarenal region, thus causing more stress damage to the endothelium, which facilities more inflammatory cell filtration into this region. Estrogen also exerts favorable changes in the cholesterol profile.10 This, too, cannot be the explanation for the effects of E2 in reducing Ang II–induced AAA and atherosclerosis in the present study, because cholesterol levels were not different from the control groups. Histological examination revealed that there were fewer intimal plaques and relatively fewer macrophages, at least qualitatively, in the intima of the aortic wall in mice treated with E2. Reduction of arterial expression of proinflammatory genes by estrogen could inhibit inflammatory cell migration into the vascular wall. On the other hand, decreased arterial expression of proinflammatory genes and transcription factors could also be a consequence of decreased number or density of inflammatory cells. The present data cannot differential such cause and effect consequence. Our data also showed that circulating leukocytes were approximately 37% lower in mice treated with Ang II plus E2 compared with those receiving Ang II only. However, the reduction in tissue macrophage by E2 is most likely a consequence of its effect in preventing endothelial activation and local production of chemoattractants. This view is supported by a report by Alvarez et al,39 who provided direct in vivo evidence that estrogen inhibits Ang II–induced leukocyte– endothelial cell interactions. Circulating leukocytes maintain their integrins in nonadhesive states, whose avidity to endothelial ligands is stimulated by endothelium-displayed chemokines.40 Our data that Ang II alone reduced circulating leukocytes by approximately 37% despite its effects in promotion of inflammatory cell migration also support the view that circulating levels of leukocytes may not directly affect their capability to migrate into the vascular wall. This is in agreement with the report by Panzer et al,41 in which the glomerular monocyte infiltration
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occurred despite a 50% reduction in the circulating leukocytes in an immune-mediated mesangial cell injury model. PPARs are members of the nuclear receptor superfamily of transcription factors that controls the expression of a large array of genes. Experimental data indicate that both PPAR-␣ and -␥ play an important role in modulating vascular inflammation. In support of this view is the observation that inflammation, provoked by arachidonic acid or its derivative leukotriene B4 (LTB4), is prolonged in PPAR-␣– deficient mice.42 Many of the anti-inflammatory responses of PPARs may result from the inhibition of the NF-B signaling pathway.43,44 This view is reinforced by a recent discovery that the anti-inflammatory prostaglandin, 15-deoxy-␦-12,14prostaglandin J2, also a natural PPAR-␥ ligand, directly inhibits IB kinase, which inactivates IB by phosphorylation.45 Furthermore, our previous study demonstrated that Ang II–induced AAA in apoE-KO mice was associated with a significant downregulation of both PPAR-␣ and -␥ expression in the aorta, thus impairing an important antiinflammatory defense mechanism.6 Diminished PPAR expression may contribute, at least in part, to Ang II–induced vascular inflammation. Treatment with PPAR agonists in Ang II–infused apoE-KO mice dramatically decreased NFB, Egr-1, and Sp-1 transcriptional activation and downregulated proinflammatory gene expression.46 Thus, the upregulation of PPAR after E2 treatment in the present study may contribute to the vasculoprotective effects of E2 through attenuation of NF-B–mediated proinflammatory gene expression. In summary, the present data indicate a broad array of cellular actions for the anti-inflammatory and vasculoprotective actions of estrogen. Attenuation of atherosclerosis and AAA by estrogen could result from its inhibition of arterial expression of proinflammatory genes and transcription factors, which consequently reduced inflammatory cell migration into the vascular wall.
Acknowledgments This work was partially supported by the BioStar (Biotechnology Strategic Alliance Research) grant. The authors thank Jefferson L. Davis for his technical assistance and the Berlex Biosciences Animal Care Group under the direction of William Lillis for the proper care of the animals over the duration of these studies.
References 1. Ross R. Atherosclerosis is an inflammatory disease. Am Heart J. 1999; 138:S419 –S420. 2. Carmeliet P, Moons L, Lijnen R, Baes M, Lemaitre V, Tipping P, Drew A, Eeckhout Y, Shapiro S, Lupu F, Collen D. Urokinasegenerated plasmin activates matrix metalloproteinases during aneurysm formation. Nat Genet. 1997;17:439 – 444. 3. Weiss D, Sorescu D, Taylor WR. Angiotensin II and atherosclerosis. Am J Cardiol. 2001;87:25C–32C. 4. Brasier AR, Jamaluddin M, Han Y, Patterson C, Runge MS. Angiotensin II induces gene transcription through cell-type-dependent effects on the nuclear factor-kappaB (NF-kappaB) transcription factor. Mol Cell Biochem. 2000;212:155–169. 5. Daugherty A, Manning MW, Cassis LA. Angiotensin II promotes atherosclerotic lesions and aneurysms in apolipoprotein E-deficient mice. J Clin Invest. 2000;105:1605–1612. 6. Tham DM, Martin-McNulty B, Wang YX, Wilson DW, Vergona R, Sullivan ME, Dole WP, Rutledge JC. Angiotensin II is associated with activation of NF-kB-mediated inflammatory genes and downregulation of PPARs. Physiol Genomics. 2002;11:21–30.
Downloaded from http://atvb.ahajournals.org/ by guest on August 22, 2015
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7. Wang YX, Martin-McNulty B, Freay AD, Sukovich DA, Halks-Miller M, Li WW, Vergona R, Sullivan ME, Morser J, Dole WP, Deng GG. Angiotensin II increases urokinase-type plasminogen activator expression and induces aneurysm in the abdominal aorta of apolipoprotein E-deficient mice. Am J Pathol. 2001;159:1455–1464. 8. Bengtsson H, Sonesson B, Bergqvist D. Incidence and prevalence of abdominal aortic aneurysms, estimated by necropsy studies and population screening by ultrasound. Ann N Y Acad Sci. 1996;800:1–24. 9. Manning MW, Cassi LA, Huang J, Szilvassy SJ, Daugherty A. Abdominal aortic aneurysms: fresh insights from a novel animal model of the disease. Vasc Med. 2002;7:45–54. 10. Mendelsohn ME, Karas RH. The protective effects of estrogen on the cardiovascular system. N Engl J Med. 1999;340:1801–1811. 11. Tse J, Martin-McNaulty B, Halks-Miller M, Kauser K, DelVecchio V, Vergona R, Sullivan ME, Rubanyi GM. Accelerated atherosclerosis and premature calcified cartilaginous metaplasia in the aorta of diabetic male Apo E knockout mice can be prevented by chronic treatment with 17 beta-estradiol. Atherosclerosis. 1999;144:303–313. 12. Bjarnason NH, Haarbo J, Byrjalsen I, Alexandersen P, Kauffman RF, Christiansen C. Raloxifene and estrogen reduces progression of advanced atherosclerosis: a study in ovariectomized, cholesterol-fed rabbits. Atherosclerosis. 2001;154:97–102. 13. Sulistiyani, Adelman SJ, Chandrasekaran A, Jayo J, St Clair RW. Effect of 17 alpha-dihydroequilin sulfate, a conjugated equine estrogen, and ethynylestradiol on atherosclerosis in cholesterol-fed rabbits. Arterioscler Thromb Vasc Biol. 1995;15:837– 846. 14. Nathan L, Pervin S, Singh R, Rosenfeld M, Chaudhuri G. Estradiol inhibits leukocyte adhesion and transendothelial migration in rabbits in vivo: possible mechanisms for gender differences in atherosclerosis. Circ Res. 1999;85:377–385. 15. Pervin S, Singh R, Rosenfeld ME, Navab M, Chaudhuri G, Nathan L. Estradiol suppresses MCP-1 expression in vivo: implications for atherosclerosis. Arterioscler Thromb Vasc Biol. 1998;18:1575–1582. 16. Evans MJ, Eckert A, Lai K, Adelman SJ, Harnish DC. Reciprocal antagonism between estrogen receptor and NF-B activity in vivo. Circ Res. 2001;89:823– 830. 17. Guyton A. Textbook of Medical Physiology. 17th ed. Philadelphia, PA: WB Saunders; 1986. 18. Daugherty A, Manning MW, Cassis LA. Antagonism of AT2 receptors augments angiotensin II-induced abdominal aortic aneurysms and atherosclerosis. Br J Pharmacol. 2001;134:865– 870. 19. Wang YX, Halks-Miller M, Vergona R, Sullivan ME, Fitch R, Mallari C, Martin-McNulty B, da Cunha V, Freay A, Rubanyi GM, Kauser K. Increased aortic stiffness assessed by pulse wave velocity in apolipoprotein E-deficient mice. Am J Physiol Heart Circ Physiol. 2000; 278:H428 –H434. 20. Chen BC, Lin WW. Pyrimidinoceptor potentiation of macrophage PGE(2) release involved in the induction of nitric oxide synthase. Br J Pharmacol. 2000;130:777–786. 21. Barnes PJ, Karin M. Nuclear factor-kappaB: a pivotal transcription factor in chronic inflammatory diseases. N Engl J Med. 1997;336: 1066 –1071. 22. Kranzhofer R, Schmidt J, Pfeiffer CA, Hagl S, Libby P, Kubler W. Angiotensin induces inflammatory activation of human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol. 1999;19: 1623–1629. 23. Ruiz-Ortega M, Lorenzo O, Ruperez M, Blanco J, Egido J. Systemic infusion of angiotensin II into normal rats activates nuclear factorkappaB and AP-1 in the kidney: role of AT(1) and AT(2) receptors. Am J Pathol. 2001;158:1743–1756. 24. Maltzman JS, Carmen JA, Monroe JG. Transcriptional regulation of the Icam-1 gene in antigen receptor- and phorbol ester-stimulated B lymphocytes: role for transcription factor EGR1. J Exp Med. 1996; 183:1747–1759. 25. Bourassa PA, Milos PM, Gaynor BJ, Breslow JL, Aiello RJ. Estrogen reduces atherosclerotic lesion development in apolipoprotein E-deficient mice. Proc Natl Acad Sci U S A. 1996;93:10022–10027. 26. Van Baal WM, Emeis JJ, Kenemans P, Kessel H, Peters-Muller ER, Schalkwijk CG, van der Mooren MJ, Stehouwer CD. Short-term hormone replacement therapy: reduced plasma levels of soluble adhesion molecules. Eur J Clin Invest. 1999;29:913–921. 27. van Baal WM, Kenemans P, Emeis JJ, Schalkwijk CG, Mijatovic V, van der Mooren MJ, Vischer UM, Stehouwer CD. Long-term effects
28.
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30.
31.
32.
33. 34.
35.
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37.
38.
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45.
46.
of combined hormone replacement therapy on markers of endothelial function and inflammatory activity in healthy postmenopausal women. Fertil Steril. 1999;71:663– 670. Simoncini T, Maffei S, Basta G, Barsacchi G, Genazzani AR, Liao JK, De Caterina R. Estrogens and glucocorticoids inhibit endothelial vascular cell adhesion molecule-1 expression by different transcriptional mechanisms. Circ Res. 2000;87:19 –25. Ray P, Ghosh SK, Zhang DH, Ray A. Repression of interleukin-6 gene expression by 17 beta-estradiol: inhibition of the DNA-binding activity of the transcription factors NF-IL6 and NF-kappa B by the estrogen receptor. FEBS Lett. 1997;409:79 – 85. Harnish DC, Scicchitano MS, Adelman SJ, Lyttle CR, Karathanasis SK. The role of CBP in estrogen receptor cross-talk with nuclear factor-kappaB in HepG2 cells. Endocrinology. 2000;141:3403–3411. Speir E, Yu ZX, Takeda K, Ferrans VJ, Cannon RO 3rd. Competition for p300 regulates transcription by estrogen receptors and nuclear factor-kappaB in human coronary smooth muscle cells. Circ Res. 2000;87:1006 –1011. Khachigian LM, Lindner V, Williams AJ, Collins T. Egr-1-induced endothelial gene expression: a common theme in vascular injury. Science. 1996;271:1427–1431. Silverman ES, Collins T. Pathways of Egr-1-mediated gene transcription in vascular biology. Am J Pathol. 1999;154:665– 670. Wu YL, Wiltbank MC. Transcriptional regulation of cyclooxygenase-2 gene in ovine large luteal cells. Biol Reprod. 2001;65: 1565–1572. Borden P, Heller RA. Transcriptional control of matrix metalloproteinases and the tissue inhibitors of matrix metalloproteinases. Crit Rev Eukaryot Gene Expr. 1997;7:159 –178. Lelievre E, Lionneton F, Soncin F, Vandenbunder B. The Ets family contains transcriptional activators and repressors involved in angiogenesis. Int J Biochem Cell Biol. 2001;33:391– 407. Takeda-Matsubara Y, Nakagami H, Iwai M, Cui TX, Shiuchi T, Akishita M, Nahmias C, Ito M, Horiuchi M. Estrogen activates phosphatases and antagonizes growth-promoting effect of angiotensin II. Hypertension. 2002;39:41– 45. Crofton JT, Share L, Brooks DP. Gonadectomy abolishes the sexual dimorphism in DOC-salt hypertension in the rat. Clin Exp Hypertens. 1989;11:1249 –1261. Alvarez A, Hermenegildo C, Issekutz AC, Esplugues JV, Sanz M-J. Estrogens inhibit angiotensin II-induced leukocyte-endothelial cell interactions in vivo via rapid endothelial nitric oxide synthase and cyclooxygenase activation. Circ Res. 2002;91:1142–1150. Grabovsky V, Feigelson S, Chen C, Bleijs DA, Peled A, Cinamon G, Baleux F, Arenzana-Seisdedos F, Lapidot T, van Kooyk Y, Lobb RR, Alon R. Subsecond induction of ␣4 integrin clustering by immobilized chemokines stimulates leukocyte tethering and rolling on endothelial vascular cell adhesion molecule 1 under flow conditions. J Exp Med. 2000;192:495–506. Panzer U, Schneider Ae, Wilken J, Thompson DA, Kent SBH, Stahl RAK. The chemokine receptor antagonist AOP-RANTES reduces monocyte infiltration in experimental glomerulonephritis. Kidney Int. 1999;56:2107–2115. Devchand PR, Keller H, Peters JM, Vazquez M, Gonzalez FJ, Wahli W. The PPARalpha-leukotriene B4 pathway to inflammation control. Nature. 1996;384:39 – 43. Delerive P, De Bosscher K, Besnard S, Vanden Berghe W, Peters JM, Gonzalez FJ, Fruchart JC, Tedgui A, Haegeman G, Staels B. Peroxisome proliferator-activated receptor alpha negatively regulates the vascular inflammatory gene response by negative cross-talk with transcription factors NF-kappaB and AP-1. J Biol Chem. 1999;274: 32048 –32054. Marx N, Sukhova GK, Collins T, Libby P, Plutzky J. PPARalpha activators inhibit cytokine-induced vascular cell adhesion molecule-1 expression in human endothelial cells. Circulation. 1999;99: 3125–3131. Rossi A, Kapahi P, Natoli G, Takahashi T, Chen Y, Karin M, Santoro MG. Anti-inflammatory cyclopentenone prostaglandins are direct inhibitors of IkappaB kinase. Nature. 2000;403:103–108. Tham DM, Martin-McNulty B, Wang YX, Vergona R, Sullivan ME, Rutledge JC. Effects of PPAR agonist on apolipoprotein E-deficient mice treated with angiotensin II. Arterioscler Thromb Vasc Biol. 2002;22:a3.
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17β-Estradiol Attenuates Development of Angiotensin II−Induced Aortic Abdominal Aneurysm in Apolipoprotein E−Deficient Mice Baby Martin-McNulty, Doris M. Tham, Valdeci da Cunha, Jerrick J. Ho, Dennis W. Wilson, John C. Rutledge, Gary G. Deng, Ronald Vergona, Mark E. Sullivan and Yi-Xin Wang Arterioscler Thromb Vasc Biol. 2003;23:1627-1632; originally published online July 10, 2003; doi: 10.1161/01.ATV.0000085842.20866.6A Arteriosclerosis, Thrombosis, and Vascular Biology is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 2003 American Heart Association, Inc. All rights reserved. Print ISSN: 1079-5642. Online ISSN: 1524-4636
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