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Gage MC, Yuldasheva NY, Viswambharan H, Sukumar P, Cubbon RM, Galloway S, Imrie H, Skromna A, Smith J, Jackson CL, Kearney MT, Wheatcroft SB. Endothelium-specific insulin resistance leads to accelerated atherosclerosis in areas with disturbed flow patterns: a role for reactive oxygen species. Atherosclerosis 2013; 230:131-9. [PMID: 23958265 DOI: 10.1016/j.atherosclerosis.2013.06.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Systemic insulin resistance is associated with a portfolio of risk factors for atherosclerosis development. We sought to determine whether insulin resistance specifically at the level of the endothelium promotes atherosclerosis and to examine the potential involvement of reactive oxygen species. METHODS We cross-bred mice expressing a dominant negative mutant human insulin receptor specifically in the endothelium (ESMIRO) with ApoE(-/-) mice to examine the effect of endothelium-specific insulin resistance on atherosclerosis. RESULTS ApoE(-/-)/ESMIRO mice had similar blood pressure, plasma lipids and whole-body glucose tolerance, but blunted endothelial insulin signalling, in comparison to ApoE(-/-) mice. Atherosclerosis was significantly increased in ApoE(-/-)/ESMIRO mice at the aortic sinus (226 ± 16 versus 149 ± 24 × 10(3) μm(2), P = 0.01) and lesser curvature of the aortic arch (12.4 ± 1.2% versus 9.4 ± 0.9%, P = 0.035). Relaxation to acetylcholine was blunted in aorta from ApoE(-/-)/ESMIRO mice (Emax 65 ± 41% versus 103 ± 6%, P = 0.02) and was restored by the superoxide dismutase mimetic MnTMPyP (Emax 112 ± 15% versus 65 ± 41%, P = 0.048). Basal generation of superoxide was increased 1.55 fold (P = 0.01) in endothelial cells from ApoE(-/-)/ESMIRO mice and was inhibited by the NADPH oxidase inhibitor gp91ds-tat (-12 ± 0.04%, P = 0.04), the NO synthase inhibitor L-NMMA (-8 ± 0.02%, P = 0.001) and the mitochondrial specific inhibitor rotenone (-23 ± 0.04%, P = 0.006). CONCLUSIONS Insulin resistance specifically at the level of the endothelium leads to acceleration of atherosclerosis in areas with disturbed flow patterns such as the aortic sinus and the lesser curvature of the aorta. We have identified a potential role for increased generation of reactive oxygen species from multiple enzymatic sources in promoting atherosclerosis in this setting.
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Sukumar P, Viswambharan H, Imrie H, Cubbon RM, Yuldasheva N, Gage M, Galloway S, Skromna A, Kandavelu P, Santos CX, Gatenby VK, Smith J, Beech DJ, Wheatcroft SB, Channon KM, Shah AM, Kearney MT. Nox2 NADPH oxidase has a critical role in insulin resistance-related endothelial cell dysfunction. Diabetes 2013; 62:2130-4. [PMID: 23349484 PMCID: PMC3661635 DOI: 10.2337/db12-1294] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Insulin resistance is characterized by excessive endothelial cell generation of potentially cytotoxic concentrations of reactive oxygen species. We examined the role of NADPH oxidase (Nox) and specifically Nox2 isoform in superoxide generation in two complementary in vivo models of human insulin resistance (endothelial specific and whole body). Using three complementary methods to measure superoxide, we demonstrated higher levels of superoxide in insulin-resistant endothelial cells, which could be pharmacologically inhibited both acutely and chronically, using the Nox inhibitor gp91ds-tat. Similarly, insulin resistance-induced impairment of endothelial-mediated vasorelaxation could also be reversed using gp91ds-tat. siRNA-mediated knockdown of Nox2, which was specifically elevated in insulin-resistant endothelial cells, significantly reduced superoxide levels. Double transgenic mice with endothelial-specific insulin resistance and deletion of Nox2 showed reduced superoxide production and improved vascular function. This study identifies Nox2 as the central molecule in insulin resistance-mediated oxidative stress and vascular dysfunction. It also establishes pharmacological inhibition of Nox2 as a novel therapeutic target in insulin resistance-related vascular disease.
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Gage M, Wheatcroft S, Abbas A, Imrie H, Viswambharan H, Galloway S, Sukumar P, Cubbon R, Smith J, Schurmans S, Jacoby M, Dubois E, Kearney M. 241 ENDOTHELIAL SHIP2 CONFERS AGE-DEPENDENT CONTRASTING AFFECTS ON WHOLE BODY GLUCOSE HOMEOSTASIS AND VASCULAR FUNCTION. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sengupta A, Viswambharan H, Yuldasheva N, Mercer B, Aziz A, Imrie H, Gage M, Gatenby V, Skromna A, Wheatcroft S, Kearney M, Cubbon R. 163 VASCULAR ENDOTHELIAL INSULIN SENSITISATION REDUCES BLOOD PRESSURE AND PROMOTES ENDOTHELIAL REPAIR IN THE CONTEXT OF GLOBAL INSULIN RESISTANCE. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sukumar P, Viswambharan H, Imrie H, Cubbon R, Yuldasheva N, Gage M, Galloway S, Skromna A, Kandavelu P, Santos CX, Gatenby K, Smith J, Beech DJ, Wheatcroft SB, Channon KM, Shah AM, Kearney MT. 195 TARGETING NOX2 NADPH OXIDASE IN INSULIN RESISTANCE RELATED ENDOTHELIAL DYSFUNCTION. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sukumar P, Viswambharan H, Imrie H, Cubbon RM, Yuldasheva N, Gage M, Galloway S, Skromna A, Kandavelu P, Santos CX, Gatenby VK, Smith J, Beech DJ, Wheatcroft SB, Channon KM, Shah AM, Kearney MT. E: TARGETING NOX2 NADPH OXIDASE IN INSULIN RESISTANCE RELATED ENDOTHELIAL DYSFUNCTION. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Mercer B, Yuldasheva N, Viswambharan H, Baliga V, Stephen S, Askham J, Sukumar P, Skromna A, Mughal R, Imrie H, Gage M, Rakobowchuk M, Li J, Porter K, Ponnambalam S, Wheatcroft S, Beech D, Kearney M, Cubbon R. 201 RESTORING AKT ACTIVITY IN LATE OUTGROWTH ENDOTHELIAL PROGENITOR CELLS FROM HUMANS AT HIGH CARDIOVASCULAR RISK RESCUES THEIR ANGIOGENIC CAPACITY. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Viswambharan H, Sukumar P, Gage M, Imrie H, Sengupta A, Turner J, Yuldasheva N, Skromna A, Galloway S, Smith J, Cubbon R, Wheatcroft S, Kearney M. 171 NOX2-DERIVED REACTIVE OXYGEN SPECIES CAUSES VASCULAR DYSFUNCTION IN MURINE MODEL OF ENDOTHELIAL INSULIN SENSITIVITY AND ACTIVATION OF NRF2 TRANSCRIPTION FACTOR. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Imrie H, Viswambharan H, Sukumar P, Abbas A, Cubbon RM, Yuldasheva N, Gage M, Smith J, Galloway S, Skromna A, Rashid ST, Futers TS, Xuan S, Gatenby VK, Grant PJ, Channon KM, Beech DJ, Wheatcroft SB, Kearney MT. Novel role of the IGF-1 receptor in endothelial function and repair: studies in endothelium-targeted IGF-1 receptor transgenic mice. Diabetes 2012; 61:2359-68. [PMID: 22733797 PMCID: PMC3425420 DOI: 10.2337/db11-1494] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
We recently demonstrated that reducing IGF-1 receptor (IGF-1R) numbers in the endothelium enhances nitric oxide (NO) bioavailability and endothelial cell insulin sensitivity. In the present report, we aimed to examine the effect of increasing IGF-1R on endothelial cell function and repair. To examine the effect of increasing IGF-1R in the endothelium, we generated mice overexpressing human IGF-1R in the endothelium (human IGF-1R endothelium-overexpressing mice [hIGFREO]) under direction of the Tie2 promoter enhancer. hIGFREO aorta had reduced basal NO bioavailability (percent constriction to N(G)-monomethyl-l-arginine [mean (SEM) wild type 106% (30%); hIGFREO 48% (10%)]; P < 0.05). Endothelial cells from hIGFREO had reduced insulin-stimulated endothelial NO synthase activation (mean [SEM] wild type 170% [25%], hIGFREO 58% [3%]; P = 0.04) and insulin-stimulated NO release (mean [SEM] wild type 4,500 AU [1,000], hIGFREO 1,500 AU [700]; P < 0.05). hIGFREO mice had enhanced endothelium regeneration after denuding arterial injury (mean [SEM] percent recovered area, wild type 57% [2%], hIGFREO 47% [5%]; P < 0.05) and enhanced endothelial cell migration in vitro. The IGF-1R, although reducing NO bioavailability, enhances in situ endothelium regeneration. Manipulating IGF-1R in the endothelium may be a useful strategy to treat disorders of vascular growth and repair.
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Cubbon RM, Viswambharan H, Baliga V, Yuldasheva N, Stephen S, Askham J, Mercer BN, Rakobowchuk MR, Sukumar P, Skromna A, Li J, Ponnambalam S, Porter KE, Wheatcroft SB, Beech DJ, Kearney MT. A Gene-based restoration of Akt activity in endothelial progenitor cells from human subjects at high cardiovascular risk rescues vascular reparative capacity. Heart 2012. [DOI: 10.1136/heartjnl-2012-301877a.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Sukumar P, Viswambharan H, Imrie H, Cubbon RM, Yuldasheva N, Gage M, Galloway S, Skromna A, Smith J, Gatenby K, Beech DJ, Wheatcroft SB, Channon KM, Shah AM, Kearney MT. 105 NOX2 NADPH—oxidase a novel target to prevent insulin resistance related endothelial cell dysfunction. BRITISH HEART JOURNAL 2012. [DOI: 10.1136/heartjnl-2012-301877b.105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Gage MC, Yuldasheva NY, Viswambharan H, Sukumar P, Cubbon RM, Galloway S, Imrie H, Skromna A, Smith J, Jackson C, Kearney MT, Wheatcroft SB. D Endothelium specific insulin resistance leads to accelerated atherosclerosis: a role for reactive oxygen species. BRITISH HEART JOURNAL 2012. [DOI: 10.1136/heartjnl-2012-301877a.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Imrie H, Viswambharan H, Sukumar P, Abbas A, Yuldasheva N, Gage M, Galloway S, Wheatcroft SB, Kearney MT. 109 Overexpression of endothelial insulin-like growth factor-1 receptors (IGF-1R): a novel role for IGF-1R in endothelial function and repair. BRITISH HEART JOURNAL 2012. [DOI: 10.1136/heartjnl-2012-301877b.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Viswambharan H, Sukumar P, Gage MC, Yuldasheva N, Skromna A, Imrie H, Galloway S, Smith J, Cubbon R, Wheatcroft SB, Kearney MT. 104 Enhancing endothelial insulin sensitivity reduces nitric oxide bioavailability: a role for NADPH oxidase-derived reactive oxygen species. BRITISH HEART JOURNAL 2012. [DOI: 10.1136/heartjnl-2012-301877b.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Rajwani A, Ezzat V, Smith J, Yuldasheva NY, Duncan ER, Gage M, Cubbon RM, Kahn MB, Imrie H, Abbas A, Viswambharan H, Aziz A, Sukumar P, Vidal-Puig A, Sethi JK, Xuan S, Shah AM, Grant PJ, Porter KE, Kearney MT, Wheatcroft SB. Increasing circulating IGFBP1 levels improves insulin sensitivity, promotes nitric oxide production, lowers blood pressure, and protects against atherosclerosis. Diabetes 2012; 61:915-24. [PMID: 22357965 PMCID: PMC3314358 DOI: 10.2337/db11-0963] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 12/29/2011] [Indexed: 12/02/2022]
Abstract
Low concentrations of insulin-like growth factor (IGF) binding protein-1 (IGFBP1) are associated with insulin resistance, diabetes, and cardiovascular disease. We investigated whether increasing IGFBP1 levels can prevent the development of these disorders. Metabolic and vascular phenotype were examined in response to human IGFBP1 overexpression in mice with diet-induced obesity, mice heterozygous for deletion of insulin receptors (IR(+/-)), and ApoE(-/-) mice. Direct effects of human (h)IGFBP1 on nitric oxide (NO) generation and cellular signaling were studied in isolated vessels and in human endothelial cells. IGFBP1 circulating levels were markedly suppressed in dietary-induced obese mice. Overexpression of hIGFBP1 in obese mice reduced blood pressure, improved insulin sensitivity, and increased insulin-stimulated NO generation. In nonobese IR(+/-) mice, overexpression of hIGFBP1 reduced blood pressure and improved insulin-stimulated NO generation. hIGFBP1 induced vasodilatation independently of IGF and increased endothelial NO synthase (eNOS) activity in arterial segments ex vivo, while in endothelial cells, hIGFBP1 increased eNOS Ser(1177) phosphorylation via phosphatidylinositol 3-kinase signaling. Finally, in ApoE(-/-) mice, overexpression of hIGFBP1 reduced atherosclerosis. These favorable effects of hIGFBP1 on insulin sensitivity, blood pressure, NO production, and atherosclerosis suggest that increasing IGFBP1 concentration may be a novel approach to prevent cardiovascular disease in the setting of insulin resistance and diabetes.
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Abbas A, Imrie H, Viswambharan H, Sukumar P, Rajwani A, Cubbon RM, Gage M, Smith J, Galloway S, Yuldeshava N, Kahn M, Xuan S, Grant PJ, Channon KM, Beech DJ, Wheatcroft SB, Kearney MT. The insulin-like growth factor-1 receptor is a negative regulator of nitric oxide bioavailability and insulin sensitivity in the endothelium. Diabetes 2011; 60:2169-78. [PMID: 21677284 PMCID: PMC3142083 DOI: 10.2337/db11-0197] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE In mice, haploinsufficiency of the IGF-1 receptor (IGF-1R(+/-)), at a whole-body level, increases resistance to inflammation and oxidative stress, but the underlying mechanisms are unclear. We hypothesized that by forming insulin-resistant heterodimers composed of one IGF-1Rαβ and one insulin receptor (IR), IRαβ complex in endothelial cells (ECs), IGF-1R reduces free IR, which reduces EC insulin sensitivity and generation of the antioxidant/anti-inflammatory signaling radical nitric oxide (NO). RESEARCH DESIGN AND METHODS Using a number of complementary gene-modified mice with reduced IGF-1R at a whole-body level and specifically in EC, and complementary studies in EC in vitro, we examined the effect of changing IGF-1R/IR stoichiometry on EC insulin sensitivity and NO bioavailability. RESULTS IGF-1R(+/-) mice had enhanced insulin-mediated glucose lowering. Aortas from these mice were hypocontractile to phenylephrine (PE) and had increased basal NO generation and augmented insulin-mediated NO release from EC. To dissect EC from whole-body effects we generated mice with EC-specific knockdown of IGF-1R. Aortas from these mice were also hypocontractile to PE and had increased basal NO generation. Whole-body and EC deletion of IGF-1R reduced hybrid receptor formation. By reducing IGF-1R in IR-haploinsufficient mice we reduced hybrid formation, restored insulin-mediated vasorelaxation in aorta, and insulin stimulated NO release in EC. Complementary studies in human umbilical vein EC in which IGF-1R was reduced using siRNA confirmed that reducing IGF-1R has favorable effects on NO bioavailability and EC insulin sensitivity. CONCLUSIONS These data demonstrate that IGF-1R is a critical negative regulator of insulin sensitivity and NO bioavailability in the endothelium.
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Abbas A, Viswambharan H, Imrie H, Rajwani A, Kahn M, Gage M, Cubbon R, Surr J, Wheatcroft S, Kearney M. A Endothelial cell nitric oxide bioavailability and insulin sensitivity are regulated by IGF-1 and insulin receptor levels. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300110.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Gage MC, Yuldasheva N, Jackson C, Kearney M, Imrie H, Viswambharan H, Kahn M, Smith J, Galloway S, Cubbon R, Sukumar P, Aziz A, Wheatcroft S. 139 Endothelial specific insulin resistance promotes the development of atherosclerosis. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300198.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Kahn MB, Yuldasheva N, Cubbon R, Surr J, Rashid S, Viswambharan H, Imrie H, Abbas A, Rajwani A, Gage M, Kearney MT, Wheatcroft S. C Insulin resistance impairs angiogenic progenitor cell function and delays endothelial repair following vascular injury. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300110.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Kahn MB, Yuldasheva NY, Cubbon RM, Smith J, Rashid ST, Viswambharan H, Imrie H, Abbas A, Rajwani A, Aziz A, Baliga V, Sukumar P, Gage M, Kearney MT, Wheatcroft SB. Insulin resistance impairs circulating angiogenic progenitor cell function and delays endothelial regeneration. Diabetes 2011; 60:1295-303. [PMID: 21317296 PMCID: PMC3064103 DOI: 10.2337/db10-1080] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Circulating angiogenic progenitor cells (APCs) participate in endothelial repair after arterial injury. Type 2 diabetes is associated with fewer circulating APCs, APC dysfunction, and impaired endothelial repair. We set out to determine whether insulin resistance adversely affects APCs and endothelial regeneration. RESEARCH DESIGN AND METHODS We quantified APCs and assessed APC mobilization and function in mice hemizygous for knockout of the insulin receptor (IRKO) and wild-type (WT) littermate controls. Endothelial regeneration after femoral artery wire injury was also quantified after APC transfusion. RESULTS IRKO mice, although glucose tolerant, had fewer circulating Sca-1(+)/Flk-1(+) APCs than WT mice. Culture of mononuclear cells demonstrated that IRKO mice had fewer APCs in peripheral blood, but not in bone marrow or spleen, suggestive of a mobilization defect. Defective vascular endothelial growth factor-stimulated APC mobilization was confirmed in IRKO mice, consistent with reduced endothelial nitric oxide synthase (eNOS) expression in bone marrow and impaired vascular eNOS activity. Paracrine angiogenic activity of APCs from IRKO mice was impaired compared with those from WT animals. Endothelial regeneration of the femoral artery after denuding wire injury was delayed in IRKO mice compared with WT. Transfusion of mononuclear cells from WT mice normalized the impaired endothelial regeneration in IRKO mice. Transfusion of c-kit(+) bone marrow cells from WT mice also restored endothelial regeneration in IRKO mice. However, transfusion of c-kit(+) cells from IRKO mice was less effective at improving endothelial repair. CONCLUSIONS Insulin resistance impairs APC function and delays endothelial regeneration after arterial injury. These findings support the hypothesis that insulin resistance per se is sufficient to jeopardize endogenous vascular repair. Defective endothelial repair may be normalized by transfusion of APCs from insulin-sensitive animals but not from insulin-resistant animals.
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Rajwani A, Surr J, Porter KE, Viswambharan H, Imrie H, Abbas A, Cubbon R, Ezzat V, Kearney MT, Wheatcroft SB. E IGFBP-1 upregulates vascular nitric oxide via PI-3-K activation and rescues endothelial function in murine models of insulin resistance: Abstract E Table 1. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.196113.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Chadjichristos CE, Scheckenbach KEL, van Veen TAB, Richani Sarieddine MZ, de Wit C, Yang Z, Roth I, Bacchetta M, Viswambharan H, Foglia B, Dudez T, van Kempen MJA, Coenjaerts FEJ, Miquerol L, Deutsch U, Jongsma HJ, Chanson M, Kwak BR. Endothelial-specific deletion of connexin40 promotes atherosclerosis by increasing CD73-dependent leukocyte adhesion. Circulation 2010; 121:123-31. [PMID: 20026782 DOI: 10.1161/circulationaha.109.867176] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Endothelial dysfunction is the initiating event of atherosclerosis. The expression of connexin40 (Cx40), an endothelial gap junction protein, is decreased during atherogenesis. In the present report, we sought to determine whether Cx40 contributes to the development of the disease. METHODS AND RESULTS Mice with ubiquitous deletion of Cx40 are hypertensive, a risk factor for atherosclerosis. Consequently, we generated atherosclerosis-susceptible mice with endothelial-specific deletion of Cx40 (Cx40del mice). Cx40del mice were indeed not hypertensive. The progression of atherosclerosis was increased in Cx40del mice after 5 and 10 weeks of a high-cholesterol diet, and spontaneous lesions were observed in the aortic sinuses of young mice without such a diet. These lesions showed monocyte infiltration into the intima, increased expression of vascular cell adhesion molecule-1, and decreased expression of the ecto-enzyme CD73 in the endothelium. The proinflammatory phenotype of Cx40del mice was confirmed in another model of induced leukocyte recruitment from the lung microcirculation. Endothelial CD73 is known to induce antiadhesion signaling via the production of adenosine. We found that reducing Cx40 expression in vitro with small interfering RNA or antisense decreased CD73 expression and activity and increased leukocyte adhesion to mouse endothelial cells. These effects were reversed by an adenosine receptor agonist. CONCLUSIONS Cx40-mediated gap junctional communication contributes to a quiescent nonactivated endothelium by propagating adenosine-evoked antiinflammatory signals between endothelial cells. Alteration in this mechanism by targeting Cx40 promotes leukocyte adhesion to the endothelium, thus accelerating atherosclerosis.
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Imrie H, Abbas A, Viswambharan H, Rajwani A, Cubbon RM, Gage M, Kahn M, Ezzat VA, Duncan ER, Grant PJ, Ajjan R, Wheatcroft SB, Kearney MT. Vascular insulin-like growth factor-I resistance and diet-induced obesity. Endocrinology 2009; 150:4575-82. [PMID: 19608653 DOI: 10.1210/en.2008-1641] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Obesity and type 2 diabetes mellitus are characterized by insulin resistance, reduced bioavailability of the antiatherosclerotic signaling molecule nitric oxide (NO), and accelerated atherosclerosis. IGF-I, the principal growth-stimulating peptide, which shares many of the effects of insulin, may, like insulin, also be involved in metabolic and vascular homeostasis. We examined the effects of IGF-I on NO bioavailability and the effect of obesity/type 2 diabetes mellitus on IGF-I actions at a whole-body level and in the vasculature. In aortic rings IGF-I blunted phenylephrine-mediated vasoconstriction and relaxed rings preconstricted with phenylephrine, an effect blocked by N(G)-monomethyl L-arginine. IGF-I increased NO synthase activity to an extent similar to that seen with insulin and in-vivo IGF-I led to serine phosphorylation of endothelial NO synthase (eNOS). Mice rendered obese using a high-fat diet were less sensitive to the glucose-lowering effects of insulin and IGF-I. IGF-I increased aortic phospho-eNOS levels in lean mice, an effect that was blunted in obese mice. eNOS activity in aortae of lean mice increased 1.6-fold in response to IGF-I compared with obese mice. IGF-I-mediated vasorelaxation was blunted in obese mice. These data demonstrate that IGF-I increases eNOS phosphorylation in-vivo, increases eNOS activity, and leads to NO-dependent relaxation of conduit vessels. Obesity is associated with resistance to IGF-I at a whole-body level and in the endothelium. Vascular IGF-I resistance may represent a novel therapeutic target to prevent or slow the accelerated vasculopathy seen in humans with obesity or type 2 diabetes mellitus.
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Viswambharan H, Carvas JM, Antic V, Marecic A, Jud C, Zaugg CE, Ming XF, Montani JP, Albrecht U, Yang Z. Mutation of the circadian clock gene Per2 alters vascular endothelial function. Circulation 2007; 115:2188-95. [PMID: 17404161 DOI: 10.1161/circulationaha.106.653303] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The circadian clock regulates biological processes including cardiovascular function and metabolism. In the present study, we investigated the role of the circadian clock gene Period2 (Per2) in endothelial function in a mouse model. METHODS AND RESULTS Compared with the wild-type littermates, mice with Per2 mutation exhibited impaired endothelium-dependent relaxations to acetylcholine in aortic rings suspended in organ chambers. During transition from the inactive to active phase, this response was further increased in the wild-type mice but further decreased in the Per2 mutants. The endothelial dysfunction in the Per2 mutants was also observed with ionomycin, which was improved by the cyclooxygenase inhibitor indomethacin. No changes in the expression of endothelial acetylcholine-M3 receptor or endothelial nitric oxide synthase protein but increased cyclooxygenase-1 (not cyclooxygenase-2) protein levels were observed in the aortas of the Per2 mutants. Compared with Per2 mutants, a greater endothelium-dependent relaxation to ATP was observed in the wild-type mice, which was reduced by indomethacin. In quiescent aortic rings, ATP caused greater endothelium-dependent contractions in the Per2 mutants than in the wild-type mice, contractions that were abolished by indomethacin. The endothelial dysfunction in the Per2 mutant mice is not associated with hypertension or dyslipidemia. CONCLUSIONS Mutation in the Per2 gene in mice is associated with aortic endothelial dysfunction involving decreased production of NO and vasodilatory prostaglandin(s) and increased release of cyclooxygenase-1-derived vasoconstrictor(s). The results suggest an important role of the Per2 gene in maintenance of normal cardiovascular functions.
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Zhu S, Viswambharan H, Gajanayake T, Ming XF, Yang Z. Sirolimus increases tissue factor expression but not activity in cultured human vascular smooth muscle cells. BMC Cardiovasc Disord 2005; 5:22. [PMID: 16018822 PMCID: PMC1190166 DOI: 10.1186/1471-2261-5-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Accepted: 07/15/2005] [Indexed: 11/10/2022] Open
Abstract
Background Sirolimus-eluting stents (CYPHER stents) demonstrated remarkable efficacy in reducing restenosis rates in patients with coronary artery disease. There is a concern of sub-acute and late stent thrombosis. Tissue factor (TF) is critical in thrombosis. This study investigated the effect of sirolimus on TF expression and activity in cultured human vascular smooth muscle cells (SMCs). Methods SMCs were cultured from human saphenous veins and aortas. Quiescent cells were stimulated with sirolimus (0.1 – 20 ng/ml) over 24 hours. Cellular TF expression and activity released into culture medium were measured. The effect of sirolimus on activation of mammalian target of rapamycin (mTOR) was measured by phosphorylation of the substrate p70s6k at T389, and activation of RhoA was measured by pull-down assay. Results Sirolimus increased TF protein level in cultured human SMCs in a concentration and time-dependent manner (about 2-fold, p < 0.01) reaching maximal effect at 5 ng/ml. The stimulation of TF expression by sirolimus was associated with inhibition of basal activity of mTOR. No effects of sirolimus on RhoA or p38mapk activation that are positive regulators of TF in vascular wall cells were observed. The stimulation of TF expression by sirolimus (20 ng/ml) was prevented by the HMG-CoA reductase inhibitor fluvastatin (1 μmol/L). However, no increase in TF activity released from SMC into culture medium was observed after sirolimus treatment. Conclusion Although sirolimus stimulates TF protein expression in human SMC associated with inhibition of mTOR, it does not enhance TF activity released from the cells, suggesting a relatively safe profile of CYPHER stents. The inhibition of TF expression by fluvastatin favors clinical use of statins in patients undergoing coronary stenting.
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