Vascular Peptide Endothelin-1 Links Fat Accumulation With Alterations of Visceral Adipocyte Lipolysis
Vascular Peptide Endothelin-1 Links Fat Accumulation With Alterations of Visceral Adipocyte Lipolysis Vanessa van Harmelen 1 , Anna Eriksson 1 , Gaby Åström 1 , Kerstin Wåhlén 1 , Erik Näslund 2 , Fredrik Karpe 3 , Keith Frayn 3 , Tommy Olsson 4 , Jonas Andersson 4 , Mikel Rydén 1 and Peter Arner 1...
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Published in | Diabetes (New York, N.Y.) Vol. 57; no. 2; pp. 378 - 386 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Alexandria, VA
American Diabetes Association
01.02.2008
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Subjects | |
Online Access | Get full text |
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Summary: | Vascular Peptide Endothelin-1 Links Fat Accumulation With Alterations of Visceral Adipocyte Lipolysis
Vanessa van Harmelen 1 ,
Anna Eriksson 1 ,
Gaby Åström 1 ,
Kerstin Wåhlén 1 ,
Erik Näslund 2 ,
Fredrik Karpe 3 ,
Keith Frayn 3 ,
Tommy Olsson 4 ,
Jonas Andersson 4 ,
Mikel Rydén 1 and
Peter Arner 1
1 Department of Medicine, Karolinska Institutet at the Karolinska University Hospital, Stockholm, Sweden
2 Department of Clinical Sciences, Danderyds Hospital, Karolinska Institutet, Stockholm, Sweden
3 Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Oxford, U.K
4 Department of Medicine, Umeå University Hospital, Umeå, Sweden
Address correspondence and reprint requests to Peter Arner, MD, PhD, Karolinska Institutet, Department of Medicine, M63, Karolinska
University Hospital, Huddinge, SE-141 86 Stockholm, Sweden. E-mail: peter.arner{at}ki.se
Abstract
OBJECTIVE— Visceral obesity increases risk of insulin resistance and type 2 diabetes. This may partly be due to a region-specific resistance
to insulin's antilipolytic effect in visceral adipocytes. We investigated whether adipose tissue releases the vascular peptide
endothelin-1 (ET-1) and whether ET-1 could account for regional differences in lipolysis.
RESEARCH DESIGN AND METHODS— One group consisted of eleven obese and eleven nonobese subjects in whom ET-1 levels were compared between abdominal subcutaneous
and arterialized blood samples. A second group included subjects undergoing anti-obesity surgery. Abdominal subcutaneous and
visceral adipose tissues were obtained to study the effect of ET-1 on differentiated adipocytes regarding lipolysis and gene
and protein expression.
RESULTS— Adipose tissue had a marked net release of ET-1 in vivo, which was 2.5-fold increased in obesity. In adipocytes treated with
ET-1, the antilipolytic effect of insulin was attenuated in visceral but not in subcutaneous adipocytes, which could not be
explained by effects of ET-1 on adipocyte differentiation. ET-1 decreased the expression of insulin receptor, insulin receptor
substrate-1 and phosphodiesterase-3B and increased the expression of endothelin receptor-B (ET B R) in visceral but not in subcutaneous adipocytes. These effects were mediated via ET B R with signals through protein kinase C and calmodulin pathways. The effect of ET-1 could be mimicked by knockdown of IRS-1.
CONCLUSIONS— ET-1 is released from human adipose tissue and links fat accumulation to insulin resistance. It selectively counteracts insulin
inhibition of visceral adipocyte lipolysis via ET B R signaling pathways, which affect multiple steps in insulin signaling.
ERK, extracellular signal–related kinase
ET-1, endothelin-1
ETAR, endothelin receptor-A
ETBR, endothelin receptor-B
FFA, free fatty acid
GPDH, glycerol-3-phosphate dehydrogenase
IRS, insulin receptor substrate
MEK, mitogen-activated protein kinase kinase
OM, omental
PI3K, phosphatidylinositol 3-kinase
PKC, protein kinase C
SC, subcutaneous
TNF, tumor necrosis factor
Footnotes
Published ahead of print at http://diabetes.diabetesjournals.org on 19 November 2007. DOI: 10.2337/db07-0893.
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.
Accepted November 13, 2007.
Received July 2, 2007.
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0012-1797 1939-327X 1939-327X |
DOI: | 10.2337/db07-0893 |