Effects of Acquired Obesity on Endothelial Function in Monozygotic Twins

Authors

  • Kirsi H. Pietiläinen,

    Corresponding author
    1. Obesity Research Unit, Department of Psychiatry; Helsinki University Central Hospital, Helsinki, Finland;
    2. Department of Medicine, Division of Diabetes, Helsinki University Central Hospital, Helsinki, Finland;
    3. Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki, Finland;
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  • Robert Bergholm,

    1. Department of Medicine, Division of Diabetes, Helsinki University Central Hospital, Helsinki, Finland;
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  • Aila Rissanen,

    1. Obesity Research Unit, Department of Psychiatry; Helsinki University Central Hospital, Helsinki, Finland;
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  • Jaakko Kaprio,

    1. Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki, Finland;
    2. Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland;
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  • Anna-Maija Häkkinen,

    1. Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland
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  • Naveed Sattar,

    1. Division of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, Scotland, United Kingdom.
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  • Hannele Yki-Järvinen

    1. Department of Medicine, Division of Diabetes, Helsinki University Central Hospital, Helsinki, Finland;
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  • The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Obesity Research Unit, Biomedicum Helsinki, P.O. Box 700, 00029 HUCH Finland. E-mail: kirsi.pietilainen@helsinki.fi

Abstract

Objective: To determine whether acquired obesity or accompanying metabolic changes such as adiponectin deficiency, insulin resistance, dyslipidemia, or visceral fat are associated, independent of genetic influences, with endothelial dysfunction by studying young adult monozygotic (MZ) twin pairs discordant for obesity.

Research Methods and Procedures: Nine obesity-discordant (intra-pair difference in BMI, 3.8 to 10.1 kg/m2) and nine concordant (0 to 2.3 kg/m2) 24- to 27-year-old MZ twin pairs were identified from a population-based FinnTwin16-sample. Endothelial function was measured by blood flow responses to intrabrachial infusions of an endothelium-dependent (acetylcholine) and an endothelium-independent (sodium nitroprusside) vasodilator. Whole body insulin sensitivity was measured using the euglycemic insulin clamp technique, and forearm and body composition were measured with magnetic resonance imaging and DXA. In addition, serum levels of adiponectin, high-sensitivity C-reactive protein, and lipids were determined.

Results: The heavier co-twins of the discordant pairs had significantly lower whole body insulin sensitivity than the leaner co-twins. Blood flows/muscle volume during infusions of acetylcholine and sodium nitroprusside were not altered by obesity. However, intra-pair differences in serum adiponectin, intra-abdominal fat, and C-reactive protein were significantly correlated with those in endothelial function. Only the relationship between intra-pair differences in adiponectin and endothelial function persisted in multiple linear regression analysis. Obesity-concordant co-twins had comparable insulin sensitivity and endothelial function.

Discussion: In young adult MZ twins discordant for obesity, acquired adiponectin deficiency rather than obesity per se is an independent correlate of endothelial dysfunction.

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