title: Human adipose tissue expansion in pregnancy is impaired in gestational diabetes mellitus.
abstract: OBJECTIVE
  During pregnancy, adipose tissue (AT) must expand to support the growing fetus and the future nutritional needs of the offspring. Limited expandability of AT is associated with insulin resistance, attributed to ectopic lipid deposition. This study aimed to investigate human AT expandability during pregnancy and its role in the pathogenesis of gestational diabetes mellitus (GDM).
  
  
  METHODS
  This cross-sectional study of omental (OM) and subcutaneous (SQ) AT collected at Caesarean delivery included 11 pregnant and three non-pregnant women with normal glucose tolerance (NGT), five with GDM, three with type 2 diabetes mellitus. Adipocyte size, capillary density, collagen content and capillary growth were measured. Affymetrix arrays and real-time PCR studies of gene expression were performed.
  
  
  RESULTS
  Mean OM adipocyte size was greater in women with GDM than in those with NGT (p = 0.004). Mean OM and SQ capillary density was lower in GDM compared with NGT (p = 0.015). Capillary growth did not differ significantly between groups. The most differentially expressed AT transcript when comparing non-pregnant and pregnant women corresponded to the IGF binding protein (IGFBP)-5, the expression levels of which was found by subsequent quantitative real-time PCR to be lower in women with GDM vs women with NGT (p < 0.0001).
  
  
  CONCLUSIONS
  The relative OM adipocyte hypertrophy and decreased OM and SQ capillary density are consistent with impaired AT expandability in GDM. The induction of adipose tissue IGFBP5 in pregnancy and its decrease in GDM point to the importance of the IGF-1 signalling pathway in AT expansion in pregnancy and GDM susceptibility.
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA, 01605, USA.
authors.forename: Raziel
authors.initials: R
authors.lastname: Rojas-Rodriguez
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Lifshitz
authors.forename: Karl D
authors.initials: KD
authors.lastname: Bellve
authors.forename: So Yun
authors.initials: SY
authors.lastname: Min
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Pires
authors.forename: Katherine
authors.initials: K
authors.lastname: Leung
authors.forename: Crina
authors.initials: C
authors.lastname: Boeras
authors.forename: Aylin
authors.initials: A
authors.lastname: Sert
authors.forename: Jacqueline T
authors.initials: JT
authors.lastname: Draper
authors.forename: Silvia
authors.initials: S
authors.lastname: Corvera
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Moore Simas
mesh_terms: D017667:Adipocytes / Q000166:cytology; D050156:Adipogenesis; D000273:Adipose Tissue / Q000503:physiopathology*; D050154:Adiposity; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002196:Capillaries / Q000378:metabolism; D003430:Cross-Sectional Studies; D016640:Diabetes, Gestational / Q000503:physiopathology*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005951:Glucose Tolerance Test; D006801:Humans; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D018919:Neovascularization, Physiologic; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001786:Blood Glucose; D018975:Insulin-Like Growth Factor Binding Protein 5; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II