title: Body fat mass and the proportion of very large adipocytes in pregnant women are associated with gestational insulin resistance.
abstract: OBJECTIVE
  Pregnancy is accompanied by fat gain and insulin resistance. Changes in adipose tissue morphology and function during pregnancy and factors contributing to gestational insulin resistance are incompletely known. We sought to characterize adipose tissue in trimesters 1 and 3 (T1/T3) in normal weight (NW) and obese pregnant women, and identify adipose tissue-related factors associated with gestational insulin resistance.
  
  
  METHODS
  Twenty-two NW and 11 obese women were recruited early in pregnancy for the Pregnancy Obesity Nutrition and Child Health study. Examinations and sampling of blood and abdominal adipose tissue were performed longitudinally in T1/T3 to determine fat mass (air-displacement plethysmography); insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR); size, number and lipolytic activity of adipocytes; and adipokine release and density of immune cells and blood vessels in adipose tissue.
  
  
  RESULTS
  Fat mass and HOMA-IR increased similarly between T1 and T3 in the groups; all remained normoglycemic. Adipocyte size increased in NW women. Adipocyte number was not influenced, but proportions of small and large adipocytes changed oppositely in the groups. Lipolytic activity and circulating adipocyte fatty acid-binding protein increased in both groups. Adiponectin release was reduced in NW women. Fat mass and the proportion of very large adipocytes were most strongly associated with T3 HOMA-IR by multivariable linear regression (R(2)=0.751, P<0.001).
  
  
  CONCLUSIONS
  During pregnancy, adipose tissue morphology and function change comprehensively. NW women accumulated fat in existing adipocytes, accompanied by reduced adiponectin release. In comparison with the NW group, obese women had signs of adipocyte recruitment and maintained adiponectin levels. Body fat and large adipocytes may contribute significantly to gestational insulin resistance.
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Svensson
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Wetterling
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Bosaeus
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Odén
authors.affiliation: Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Odén
authors.affiliation: Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Jennische
authors.affiliation: Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Edén
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Holmäng
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Lönn
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D052242:Adiponectin / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D050218:Body Fat Distribution; D015992:Body Mass Index; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D009765:Obesity / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size; D011247:Pregnancy; D011248:Pregnancy Complications / Q000378:metabolism* / Q000473:pathology; D050151:Subcutaneous Fat / Q000378:metabolism
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; D001786:Blood Glucose; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D007328:Insulin