title: Regional variations in the relationship between arterial stiffness and adipocyte volume or number in obese subjects.
abstract: BACKGROUND
  Cardiovascular disease is associated with multiple risk factors including stiff arteries and large adipocytes. Whether the latter two are interrelated is unknown. We aimed to determine whether arterial stiffness is associated with fat cell size and number in subcutaneous or visceral white adipose tissue (WAT).
  
  
  METHODS
  A cross-sectional study of 120 obese subjects scheduled for bariatric surgery in whom WAT mass and distribution was assessed by dual-X-ray absorptiometry. Biopsies from visceral (greater omentum) and subcutaneous (abdominal) WAT were obtained to calculate fat cell volume and number. Arterial stiffness was determined as aortic pulse wave velocity (PWV).
  
  
  RESULTS
  Visceral adipocyte volume, but not number, was strongly (P<0.0001) and positively correlated with PWV, explaining 20% of the inter-individual variations in this parameter. This relationship remained significant after correction for clinical confounders. PWV correlated positively (r=0.38, P<0.0001) with visceral (but not subcutaneous) WAT mass. Furthermore, PWV was also positively associated with subcutaneous adipocyte volume (r=0.20, P=0.031) and negatively with fat cell number (r=-0.26, P=0.006). However, the relationships between PWV and visceral WAT mass or subcutaneous fat cell size/number became non-significant when controlling for visceral fat cell volume. In a multiple regression analysis to determine the factors that explain variations in PWV, only visceral fat cell volume, age, pulse rate and diastolic blood pressure entered the model, together explaining 42% of the variation in PWV.
  
  
  CONCLUSIONS
  Visceral fat cell volume was the only WAT parameter that constituted an independent and significant, positive regressor for arterial stiffness determined by PWV. Although a causal relationship is not established, visceral fat cell volume may explain the well-known correlation between central fat mass, arterial stiffness and cardiovascular risk, at least in severely/morbidly obese subjects.
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Arner
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Bäckdahl
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Hemmingsson
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Stenvinkel
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Eriksson-Hogling
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Näslund
authors.affiliation: 1] Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden [2] Department of Surgery, Karolinska Institutet, Ersta Hospital, Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Thorell
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: D P
authors.initials: DP
authors.lastname: Andersson
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Solna, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Caidahl
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Rydén
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000378:metabolism*; D000328:Adult; D000367:Age Factors; D050110:Bariatric Surgery; D002318:Cardiovascular Diseases / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D048429:Cell Size; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009767:Obesity, Morbid / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D012307:Risk Factors; D059289:Vascular Stiffness